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clockworkmiller
01-01-2002, 04:38 AM
What, if any, scientific explaination is there for the effects of a closed bolt versus an open bolt on a paintball's accuracy?

A lot of people have bought into the WGP's advertising of a cocker being more accurate gun that gets better distance. I am aware that distance is determinded by velocity, and accuracy is mainly determined by the barrel and paint. But could other factors in the gun play into these, and if so, how?

Minimag4me
01-01-2002, 04:43 AM
there is no difference between open and closed bolt, check somewhere on www.warpig.com they did a test

the only other way to affect accuracy and distance is spin, whick you have witnessed with that big bertha hand cannon of yours

clockworkmiller
01-01-2002, 04:51 AM
thats what I figured, thanks.

liigod
01-05-2002, 05:16 AM
one thing that the closed botl gns do have is less blowback, but they also feed slower so its a plus and a minus. I will only shoot a closed bolt gun personally. I understand that there is almost no reason for it. But my cocker shoots straighter than my mag with the same paint to barrel match as my mag. I dont know why i dont care why. it does.

Jonny05
01-06-2002, 03:02 PM
Accuracy is also determined by the "pre-coil" and "recoil" of the gun. Meaning if there is a lot of jump to the gun right before it shoots it will be less accurate. When there is a lot of recoil it will lead to an inaccurate second shot, third, and so on (in rapid fire). On cockers since only a hammer moves before the shot there is little precoil so it is considered accurate.

Also if you were to eliminate any reciprocating weight in the gun when firing it will increase accuracy. ie. using delrin, teflon injected nylon, or milling or turning down on internals like bolts and valves.

Or you could just hold your gun tighter :p

Tim Jacobitz
01-06-2002, 04:37 PM
warpig.com has a good article about open vs. closed. the article proves there one does not work better than the other

Cha0tic
01-06-2002, 05:57 PM
in an unrealistic enviroment, where recoil does not matter, accuracy is not effected. in real life, the recoil can make a slight difference, but not very much. the delrin bolts should take care of some of the problem with the mags recoil...

Jonny05
01-07-2002, 04:48 PM
What I have also noticed...

When a ball is in a chamber of an Open bolt gun and that chambers diameter is larger then .69'' the ball will litterly have to "jump" up into the breech of the barrel. This will cause a slight forward spin... BAD. It is hard to notice but ask angel owners about a slight hook they are incountering (angel breeches are big). I thought my theory would be wrong but then I heard about 12-15 people talking about it on the pbnation.com forum.

After that to only thing that can affect accuracy is gas disturbation on the ball. Not too many guns have this prob.

After that its all paint and wind.

Thats my home grown $0.02.

- Jon Kaye (no relation I think) aka JONNY.

Potatoboy
01-07-2002, 04:53 PM
This jump is exactly why 'Mag work by dropping the ball directly into the barrel. This is also the reason do not like the Freak Barrel system, since the "back" is a very large bore that you put inserts into there will *always* be that jump.

Jonny05
01-07-2002, 05:07 PM
Freak barrels will actually be worse then lets say an All American/ DYE/ etc because of the large breech and the smaller insert (for mags).

Mags have great potiental for being extremely accurate.

Since most other open bolt guns have a bore of .69'' (Impulses, Matrixes, Bushies) There is still the little jump. Hardly enough to effect accuracy but it is still there... Just more for angels.

The only thing holding mags back is "pre-coil" and recoil. Get rid of that and you have the most wanted gun on the market.

-Jon Kaye AKA JONNY

If you want to flame me e-mail me... I like discussion on this topic.

AGD
01-07-2002, 07:27 PM
Nice discussion here guys. Yes lets say that reciprocating weight does have an effect on recoil and gun movement. Then by that thinking a heavy gun would be at an advantage because it's greater mass would move less. Do you see any accuracy difference between light an heavy markers?

AGD

ps someone measure the weight of a cocker hammer and rod and a Superbolt.

Jonny05
01-07-2002, 07:56 PM
But who would want to add more weight? The only other thing you can do is have something move in the opposite direction of the origional reciprocating weight to cancel out the movements.... Seems not worth it just to eliminate a bit of recoil- not to mention things that could go wrong with the device.

You are better off finding a way to move less parts in a gun with light parts. NOT EASY. I managed to get an amazing Impulse hammer mod that takes off a lot of recoil. Still ave a little "jump" into the barrel but I'm not about to drop 500$ for a new Body to turn it into a mag type barrel.

But like I said... hold the gun tighter. Seriously it works.

-JONNY

hitech
01-08-2002, 05:10 PM
Originally posted by Jonny05
... hold the gun tighter. Seriously it works.

I'm with ya there. I have to have a shoulder "stock".

As far as open vs closed , way back before the automag there were basically two different types of semi auto paintball guns. There were the closed bolts (one by Glenn Palmer and one by Bud Orr) and open bolt blow back guns. The blow back guns had the bolt attached to the hammer. When you fired the gun the hammer shoved the bolt forward driving the paintball into the barrel and then cracking open a valve to fire the gun. Considering the consistency (or lack thereof) of paintballs the force required to shove the paintball into the barrel would be different. Since the hammer was attached to the bolt the force with which the hammer struck the valve would also be different, causing inconsistent velocities. Also, the moving parts were heavier, causing more precoil/recoil (ie, the gun moved more). At least, that was the prevailing theory at the time.

clockworkmiller
01-08-2002, 06:15 PM
If the heavier guns do produce less recoil, since it's harder to move, then that would make a cocker more accurate than a mag, just because it weighs more.

I havnt read anything about a ball "jump" before, but that would make some sense. The only thing I can see is that it may cause more ball breaks, if the ball is hitting a lip, causing it to jump.

Jonny05
01-08-2002, 08:24 PM
You have to put it into categories.

Out of the blue lets say...

Paint is 10-15% of accuracy.
Gun precoil (varies with weight and moving parts) is 10-15%
Jump is 5-10%.
Gas dynamics is 2-5% of it.
Barrel is 30-40% of it.

That is completely random but you get the idea. To actually get a test you would need lots of time and money. Back to the point-> BY MAKEING A GUN HEAVIER YOU WONT CURE TE OTHER PROBLEMS. It may in fact hinder your play.

**other factors like ball detents and recoil are not even taken into consideration**

CLOCKWORKERMILLER-Ball jump or forward roll is something I thought of when making a few custom angel bolts (realizing the larger diameter). I figured it wouldn't have any effect but I watched many people talking about it. So many with different bolts, barrels, gas systems, paint, etc. Still one factor is the same in all cases... the 18mm chamber (big trip on barrel lip).

Anyone care to disagree with my theory or give me the cash to test?

clockworkmiller
01-08-2002, 08:49 PM
Well, if you want, I might be able to arrange some sort of testing.

Just to make sure, if the a barrel is made for two different guns, it would still have the same bore size, like exact same for purpose of testing accuracy?

Jonny05
01-08-2002, 09:10 PM
Shure go ahead if you have a fancy dancy ballistics lab. :p

If you do it, do it right. Doing it the right way will cost money.

I don't have the money, connection, guns, money, or money to do it sooooo....

Anyone eles want to give it a try whos loaded?

-JONNY

clockworkmiller
01-08-2002, 10:27 PM
Im not loaded, but I have friends who have different types of guns (Angel, Mag, Cocker, m98, and Spyder).

Im sure we can figure out a way to test it.

Tom, you've got the dyno, and the whole AGD ballistics lab, you want to try it out?

Jonny05
01-09-2002, 02:08 PM
You would have to eliminate the other factors to test for each catorgy.

For ball jump you would have to use the same air system, paint, barrel (check with dial indicator), and clamp down the guns so the precoil doesn't count. Changing up bolts would help too. Like I said... It would take some connections and money.

The paint would have to be two coloured and place in so you may see if there is any spin. It would have to be indoors and with a lot of paint.

Tom want to give it a try?

AGD
01-15-2002, 09:51 PM
In my experience no matter what facts you come up with everyone ends up saying "yea but it depends" and the argument goes on.

We spent the time and money years ago. If there was anything to be had for better accuracy it would be worth a million dollars to AGD. We would have gone in that direction.

If you want to think XYZ is better that's fine go ahead.

AGD

clockworkmiller
01-16-2002, 02:04 AM
But I dont want to "think" something is better.

Any opinion that isnt based on factual evidence is an uninformed, and poorly supported opinion.

Im just saying, the easiest way to test it would be take two guns, give them the same barrel, the same paint, and same air system, same regulator, and then have at it.

If you put a case through each gun, then any small inbalances would be negated, and the only factor that should effect accuracy would be the bolt, whether it is closed or open.

Personally, I think there is a difference, but it is such a minimal difference that it would have no bearing in a fire fight. Thats based on the tests I've seen. I would like to see it between difference guns.

Apocolypse
01-18-2002, 01:10 PM
somebody came out with a new electro kit for a cocker, which lets the marker operate in both open and closed bolt. it will be interesting to see how many people buy this upgrade just to see if closed bolt really is better.

Vegeta
01-19-2002, 05:00 PM
The ppl that make the new electropnematic cocker upgrades also make the mayhem.. can't recall the company name. I am gonna post what I said in IRC earlier today.. doesnt have much to do with the discussion, but.. well.. :
"To me, Bud Orr isn't innovative.. <B>*POOF*</B>

AGD
01-20-2002, 02:40 AM
There is another comparison to make with the barrel jump scenario. Real handguns kick like a mule and jump several inches, by the same thinking they should not be able to hit ANYTHING! So why ARE real handguns accurate? Good Deep Blue question, answer that and you will know the answer to paintball gun kick vs accuracy.

AGD

Lord Vader
01-20-2002, 03:07 AM
The reason that handgun jump has little effect on handgun accuracy is simple: the bullet is traveling so fast that it leaves the barrel before the barrel jumps due to recoil.

As far as open bolt versus closed bolt, there is only ONE reason the cocker is a closed bolt gun: it is based off the Sniper pump gun. So, instead of being a semi-auto in the traditional sense, it is in fact a pneumatically pumping pump gun. Also, any movement caused by the mag bolt loading the ball into the chamber is negated by the barrel. As far as accuracy goes, (barring spin), the barrel is the great equalizer of paintguns. Once into the breech(sp?), then it's fair game as far as the paintball is concerned.

Well, I'm tired. Good night.

AGD
01-21-2002, 12:38 AM
Vader gets big points for that answer.

AGD

Lord Vader
01-21-2002, 12:45 AM
Thanks Tom. I am just trying to bring a little rational thought to the often hyped world of paintball.

steveg
01-21-2002, 11:22 AM
clockwork apparently your wish will be answered one day.
Billmi responded to a post a while ago stating that he
is going to do such a test.

If you think about it matching the barrels are easy

Extreme's,matrix,excaliburs and of course cockers all use
the same barrels. So just use the same barrel!

Second option is a freak system, same insert, same tip(front)
just the back changes Essentially the same barrel.

kenshinkandon
01-21-2002, 01:46 PM
I have an idea about being able to swap the same barrel on to different guns what about a diablo matrix which is closed bolt and say an angel(the only reason I suggested that is because they don't make automag breeches)the only thing you have to do with a matrix is change the breech and you can put on just about any barrel you want from spyders to autocockers.

liigod
01-21-2002, 09:10 PM
Well being a converted pump isnt the only reason for a cocker to be closed bolt. i personally have made an open bolt cocker. Switch the 3 way hoses then timed it differently. So there is a small advantage to having it closed i gaurentee it.

Minimag4me
01-21-2002, 10:24 PM
i agree that on a cocker closed bolt is an advantage because it was designed that way. YOu can make an open bolt cocker pretty easily but you will see negitive effects. On mags for example open bolt works best and closed has disagvantages(like not being able to operate).

In truth all markers fire in a closed bolt position.

clockworkmiller
01-21-2002, 10:33 PM
not really, senior minimag4me.

A closed bolt gun fires without any blowback. This is because the bolt is as forward as it can go when the gas is released.

With an open bolt gun, the gas is released while the bolt is moving forward, causing some of the gas to travel up into the feed.

Minimag4me
01-21-2002, 10:47 PM
ill use tippmann as an example,

the bolt moves the whole way forward(guide spring) and pushes the ball into the barrel. At the most forward position the hammer hits the valve pin and releases the gas behind the ball and the bolt/hammer steup recocks. This happend on all open bolt blow back guns. The exception is on blowforward like mags i think they have thee power piston length set so the gas is released when the bolt is pretty far forward(probably not completely closed bolt but close enough with the long nose bolts)

blowback is just remaining air in the breach(or prereleased air in shortnosed bolts). When the bolt moves to the cocked position it can go into the feed tube causeing blowback. ON a cocker(any closed bolt gun) by the time the bolt goes back to load a ball there is no extra gas in the breach.

BlackVCG
01-22-2002, 12:41 AM
Minimag4me has the idea down. The bolt stem is designed so that the pressure is released at the end of the stroke. The current PT tip with the taper is designed to release the pressure over a longer interval. The old PT tip that was counterbored released the pressure in a quick burst. You can basically control how you want the pressure released and at what time by changing the design of the PT tip.

The I.D. of the PT tip is critical also. Take a spare PT tip and drill it out 1/16" larger and observe the results. It's quite interesting. :)

Jonny05
01-23-2002, 08:39 AM
Have paintball markers become as accurate as the can be?

Well due to the fact no one agrees with my "ball jump" factor I was thinking of maybe the only other thing is to change the paintball design. I thought there were seemless balls that a whole bunch of campanies are working on. Thoes would be great in the Z-bodies and flatlines.

Thinking about it the only way you can get more accuracy is make a conical (sp?) shaped projectile then spin it like in a armson barrel. It would kinda be like a fooball/bullet. Or even better then that, a sabot (hourglass shape) shaped paint. Like the new slugs by Winchester arms. (Its gotta scare some pballs by saying that)

Naw it will never work. Paintballs will allways be
paintBALLS.

Oh yea... If anyone does the tests on ball jump tell me how it goes.

-JONNY

clockworkmiller
01-23-2002, 03:25 PM
Paintballs will as be spherical. This is because it is the easiest to load, and the most painless when getting shot. A solid front or a pointed front would definately be more prone to injury and also have to necessitate a completely redesigned gun, loading system, and rules.

Jonny05
01-23-2002, 04:39 PM
That is why I said it would never work. I think balls are the best idea.

But FYI the sabot (what winchester calls them) is shaped like an hourglass and has no point thats why I said it would be better. So it is like two cones faceing into each othere and the end(s) are rounded/flat.

I thought SP, WGP, and AGD have been testing seemless paint. Same with RPS but I heard all that from not-so-good sources.

Vegeta
01-23-2002, 06:47 PM
"To me, Bud Orr isn't innovative.. he was just a tubby guy who didn't wanna pump his WGP Sniper II so he put a ram on it. OOOooooooH! Tubalard at work!"

BTW I did mention the pump in my quote there. lol.

So it pumps itself. Its like two machines in one and therefore its not really semi auto. Its like putting mechanics on the pedals and steering wheel off a car and controlling it with a computer. Is the car really driving itself? No, it has a computer sttering it. Two diffrent mechanisms. Just liek the ocekr. automated pump.

Manuel_FZR
01-26-2002, 10:16 AM
To the accuracy point:
The accuracy depends for 95% on the paint/barrel match - thatīs definit.
My mini has the same accuracy of the Spearhead Cocker of a teammate.
Recoil is a point, but I recognized, if you shoot long bursts, recoil isnīt the problem, because you automaticaly aim the right way.
For the recoil-problem, a lighter bolt is the best way to solve - because of this, I have the VenomBolt in my Mini - itīs less than half the weight of the original hardnose. My Mini has nearly 0 recoil :D

IanR
01-30-2002, 05:32 PM
i just wanna throw this in and say: " a paintball gun will only be as accurate as its ammunition" this is true with all "real" firearms too. thats why really high grade paint is more accurate then crap paint even if both are matched with barrel perfectly. by good paint i mean seamless,heavy fill,consistent in size from ball to ball (as much as possible) just my thoughts

later

Vegeta
01-30-2002, 07:07 PM
BLACK U TOTALLY RUINED MY QUOTE!

eh.

There will be new ideas. No one has mentioned a Trap Door boltless feed here yet. (I.E. the Epic) I'd liek to hear some arguements on that.

deded
02-08-2002, 07:50 PM
Since this is deep blue after all... I figured I might mention some physics :D

I saw a post by Tom a while back that said that no deformation was seen on the dyno and with high speed photography or something... so this is probably totally wrong.

All quotes are from Physics: third edition by douglas giancoli.


In a collision of two ordinary objects, both objects are deformed, often considerably, because of the strong forces involved

It seems that this would make a closed bolt design more accurate then an open bolt design, except for at high rates of fire. I.E. The ball is pushed into the chamber and deformed, but has time to reshapen before the blast of air pushes it out of the barrel... where as the open bolt hits the ball, deforms it, and then instantaneously shoots it out the barrel, possibly not allowing the ball to re-round as quickly as the closed bolt would.

But, as no deformation was detected with high quality instruments, maybe the deformation happens for such a short time that it does not effect the accuracy of the ball at all.

If this is true, then "trap door" style boltless designs don't have much of a use... because it seems like the trap door could chop a ball just as easily as a bolt. However, a boltless design may have less precoil and recoil.

The million dollar question... what will make a more accurate paintball marker? I think the answer is: eliminate the possibility of user error. In the angel forum on pbcity, there is a guy complaining about bad accuracy when he reaches high rof. I think that this is because he is trying so hard to shoot fast that he is wobbling the angel all over the place.

So the million dollar project that AGD could design: intellifire! :D

Jonny05
02-09-2002, 06:12 PM
I can get a brain wave to micro switch adapter at Walmart right? :p

Though something like that would be damn cool it would be dangerious. There is actually people working on computer games that are controlled by your brainwaves.

But back to accuracy in paintball...

Another thing I think causes good accuracy is a short soft trigger pull. There is less jerk and no strain when you pull. I do a bit of plinking and one of the fist things you learn is to exhale takeing the shot and squeese the trigger- don't jerk it. With electronic triggers it is easy to come by but still some people still screw it up by fanning.

MORE SATURDAY RAMBLINs'- where are my phy. notes.

Wait a sec deded... how does a ball become deformed being pushed into a barrel??? Nothing is collideing in your gun when you fire because one object (the ball) is at rest. The ball has very little resenstence when struck by the bolt. So the ball will be put in motion by the greater force acting on it. After it is in motion it will want to stay in motion- the only other force is the gas, bore resistance, then the usual gravity/air resistance. If anything it will be the gas that causes the deformation because of its greater force. But here is the thing- balls can handle the force.

So what I'm basically saying is the bolts force will not do any harm to the ball because it is smaller compared to the force of the gas.

any arguements?

-JONNY

deded
02-11-2002, 12:18 AM
but....

I'm reading straight from the book here, and trying to interpret it as best I can to apply to the subject.

It is basically saying that everything is deformed by a collision. (and it is a collision... regardless of the fact that the paintball starts at rest) Even the bolt is deformed an enormously minescule amount... if I'm interpretting corectly. But, like I said, it probably all happens so quickly that it has no relevence to accuracy.

I think that the bolt must exert a good amount of force on the ball, just to move it into the barrel so quickly. And look at what happens using only the force of the bolt when the ball isn't loaded all of the way into the breech!

I personally don't believe that closed bolt (cockers in particular) shoot any straiter then open bolt. I think that some people say that cocker's are more accurate because they don't want to admit that they bought an expensive marker just because its cool and it looks good.

I own a cocker (because its cool, and it looks good) and I can't shoot it any straiter then my mag or angel. It actually shoots less accurate because I never really learned the trigger, and I wobble all over the place trying to get the ROF that I can pump out of my mag/angel.

I think we should use the collective brain of AO and deep blue to think of something that AGD might be able to develop to raise the bar of accuracy/precision in paintball!

kilaueakid
02-11-2002, 01:55 AM
Reffering back to what Lord Vader said about the accurracy thing in relation to speed of the bullet in a hand gun and how it is more accurate because the bullet has left the barrel before the recoil happens.

So than in therory, wouldn't a shorter barrel cause less recoil and therefor be more accurate because the ball will be out of it sooner?? Like a 14" vs 8"?

We should get some of the math wizards to figure out how long of a barrel you would need for the ball to leave before the bolt cycles back to the cocked position.

That would be interesting info.

kila

AGD
02-11-2002, 11:10 PM
The ball leaves the barrel in about 3 thousandths of a second. This is long before the gun starts moving anywhere.

AGD

Lord Vader
02-11-2002, 11:19 PM
Great minds think alike, eh Tom? ;-)

If you need a nuclear engineer at AGD, lemme know.

kilaueakid
02-12-2002, 07:08 AM
Quote
"The reason that handgun jump has little effect on handgun accuracy is simple: the bullet is traveling so fast that it leaves the barrel before the barrel jumps due to recoil"


So than this same info is true with paintball guns since the ball leaves long before the gun moves.

Now try squeezing off 9-12 shots a second on a handgun and tell me how accurate it is.

I think Tom holds the answer for better accuracy in paintball markers with items like there military paintball with the fins on the face of it. Paintball technology/design has to change before leaps and bounds are noticed in the accuracy department.

kila

snipey
02-12-2002, 04:51 PM
Originally posted by Jonny05
Wait a sec deded... how does a ball become deformed being pushed into a barrel??? Nothing is collideing in your gun when you fire because one object (the ball) is at rest. The ball has very little resenstence when struck by the bolt. So the ball will be put in motion by the greater force acting on it. After it is in motion it will want to stay in motion- the only other force is the gas, bore resistance, then the usual gravity/air resistance. If anything it will be the gas that causes the deformation because of its greater force. But here is the thing- balls can handle the force.

So what I'm basically saying is the bolts force will not do any harm to the ball because it is smaller compared to the force of the gas.

any arguements?

-JONNY

The ball does have resistance to the impact of the bolt, because the ball has inertia, which is the tendency of objects to forcefully remain at rest. The speed and weight of the bolt easily overcome the ball's inertian and (collision #1) send it into the barrel. The ball is then propelled (collision #2) by the gas. The paintballs inertia after it's hit by the bolt is still much less than the inertia of the expanding gas and the collision of the gas and paintball propell the paintball forward to allow the gas to continua to expand untill it reaches approx 101.3kPa (1 atm, 14.6 psi). Before the gass is there, the ball recieves the pressure equal to the gases pressure (up to 31027.5 kPa, 306.3 atm, 4500 psi). Both collisions have potential to deform the ball, with the gas being more powerful of a force, with a longer length of time to deform the ball.

notes and formulae for anyone else:
pressures are approximated to 1 decimal only

intertia = mass of object * velocity

1 atm(atmosphere) = 101.3 kPa (kiloPascal) = 14.6 psi

acceleration = force applied / mass of object
(I don't have the mass of a paintball, but plug this to find out the force applied to the paintball, if you do.)
so: am = f
( m/s2)(mass of paintball) = (force applied)

all units are metric (grams, meters, newtons, liter, etc.)

314159
02-13-2002, 01:45 PM
i see that nobody has mentioned lock times. (the time from when you pull the trigger to when the gas starts pushing the paint past the breech). the shorter the lock time, the faster the response of the marker, and the more effective that it would be in hitting a moving object.

Conqueror
02-22-2002, 09:28 PM
Snipey: The ball never receives anything close to 306 bar of pressure. More like 10 bar, at the most (according to AGD). Even if you somehow managed to get 4500 psi into the firing chamber of your gun without killing yourself, by the time it reached the paintball from the chamber it would have dropped considerably.

I'm not really sure why you listed all those equations; you didn't use any of them.

Peace.

CQ

snipey
02-23-2002, 12:14 PM
i figured that if you were intelligent enough to get as far as my post, you would know that 4500psi is definitely not the output pressure of an air tank. remotes are only rated up to 3000psi, so if you at least know your gear you could make the assumption that the air is regulated right out of the bottle!!! the equations were posted because, at the time, i did not know the mass of a paintball. i left them for someone else to plug-and-play. let's stop nit-picking post and keep to the subject now, ok?

DPB
02-27-2002, 11:36 AM
I only read through 3/4 of an argument between cockers and mags and accuracy on closed vs open bolts. Also, I read many factors which each side states. However, with real firearms you would put the gun on a benchrest and measure the MOA or Measurement of Angle. Basically this measurement (inches the aim is off-center at a certain yardage), tells exactly how accurate a certain gun is point-zero. Of course the measurement is only effective for certain documented factors: wind, temp, humid, nitro press, ball, bolt, reg, etc. Kickback or recoil is an X factor controlled and variable by the person firing the gun.

What is your take?

apache
02-27-2002, 01:11 PM
Originally posted by BlackVCG
Minimag4me has the idea down. The bolt stem is designed so that the pressure is released at the end of the stroke. The current PT tip with the taper is designed to release the pressure over a longer interval. The old PT tip that was counterbored released the pressure in a quick burst. You can basically control how you want the pressure released and at what time by changing the design of the PT tip.

The I.D. of the PT tip is critical also. Take a spare PT tip and drill it out 1/16" larger and observe the results. It's quite interesting. :)

I don't have a drill so, Black, could you tell what the results are? Does the velocity consistency get any better or would the efficiency drop?

I have the old PT tip, would it help anything if I had the step inside smoothed?

LSUMAG58
02-27-2002, 06:45 PM
towards the top of the thread yall talk about the pre-coil and recoil of a mag decreasing its accuracy. what add-ons can decreas pre-coil/recoil and do you think that they would be worth getting

-LSU

Minimag4me
02-27-2002, 08:53 PM
i think the only thing that can reduce precoil and recoil is the superbolt due to its lightweight nature.

Rusty_Jones
03-01-2002, 05:45 AM
Originally posted by AGD
There is another comparison to make with the barrel jump scenario. Real handguns kick like a mule and jump several inches, by the same thinking they should not be able to hit ANYTHING! So why ARE real handguns accurate? Good Deep Blue question, answer that and you will know the answer to paintball gun kick vs accuracy.

AGD

Okay, I didn't take physics or any math past geometry so bear with this half-brained post...

Some law in physics states for every action there is an opposite and equal reaction. There are also exceptions to this law, which I'm not a physics major or rocket scientist so I don't know it very well but it's not hard to understand in practice. Which has something to do with recoil. Hammer hits the primer in a handgun, bullet is sent down the barrel. There's some rearward forces, energy mostly, and it's related to the muzzel energy. This energy is directly transferd to your hand and through it to your wrist, you wrist is now the recoil compensator. It angles back and upward, resulting in muzzel rise. Energy is still present and it travels to your elbow and shoulder. Gun manufacturers put holes in the end of the barrel to help step this down or a gunsmith does this. Most of the time it's just in the top, so the muzzel flash (still igniting gunpowder and gasses) is directed up, which is like a mini-rocket blast, pushing the barrel back down to ease the muzzel climb. The bullet is long gone and into it's target or flying until it loses it's velocity or hits something you didn't want to. Tom mentioned it takes some fraction of a second for the round or paintball to leave the barrel.
That's right, the projectile is gone before the rest of the forces at work happen.

The accuracy this relates to is the fact that you have to return your hand, wrist, elbow, or shoulder back to the correct position to shoot again. If you had no recoil (I'm not sure that's possible), you'd just have your natural inability to hold perfectly still to defeat to remove this movement from the factors working against you for accuracy.
So, like someone previously said, hold the gun tighter, it helps.


I'd like to address the Freak Barrel system real quick too.
The amount of room involved where there's any wiggle to make a difference is about the size of a paintball. So once the gasses come out the powertube, the ball is already against the sleeve on the inside, so there is no real wiggle to make the ball less accurate. So if you're considering a Freak, it's still a good purchase.

Hope this post makes some sense to someone besides myself, it is very late after all. :)

Bob Mundon
03-06-2002, 10:13 PM
at under 50 yards a pistol will be virtually dead on accurate, the reason its inaccurate when you fire 6 shots a second is the user, not the gun. a gun will shoot where you point it at, if it missed, you did something wrong.

on of the reasons paintballs are inaccurate is they are a round shape, and round projectiles are not as effecient and build up more turbulence than a conical projectile, which is why bullets are conical. i know rifling in guns makes the bullet more stable but i remember hearing that it didnt do anything in paintball guns but i cant imagine why it wouldnt effect it.

samvalentine
03-18-2002, 01:07 AM
it dose not work because paintballs are round soft liquid filled objects.
bullets are cylindrical and made out of metal. they are harder. they ride the rifling grooves.
paintballs do not. there like water balloons not bullets.

pblunchbox
04-04-2002, 10:53 PM
When you qoute the Warpig article, make sure to remember that it was only tested to 25 feet. I agree that 25 feet is the AVERAGE fire fight for a front player. I on the other hand play back. My cocker shoots further at 285 that my mag.
It shoots further than my friends Angel. All with the same barrel and same paint. Why? well that i cannot answer. I can simply tell u that if you go to a chrono and put the barrel of all 3 guns on the little ledge you get the same reading +/- 3 fps but if you stand back 10 feet the cocker is shooting faster. No i again dont know why. Sorry for the not answerd questions. If you have the answer to that please feel free to let me know.
Oh yeah feel free to poke holes in my statements. i am simply going off what i have seen first hand.

Paladin
04-05-2002, 08:19 AM
Vegeta writes:
"To me, Bud Orr isn't innovative.. *poof* !"

Just to set the record straight:
Bud didn't put a ram on his guns until I showed him how to adapt my system to his guns. However, you are close to the reason why pumps got automated. I built the first functional, gravity fed semi for myself in the fall of 1988 because I have a very bad shoulder left over from a Hi-school football injury and the act of pumping a paintgun several hundred times a day was killing me. I was faced with a choice of either figuring out how to automate my gun or basically quit playing Paintball. I was too badly hooked on the game to quit.

Vegeta
04-07-2002, 05:37 PM
LOL i cant belive someone actually dug up that quote...

I didn't really mean to dis Bud... but now that I know if was really your idea... hmmm.. I mean your first few pump to semi conversions looked awesome, in my opinon. It's more of a nostalgig feeling of playing with a gun like that than it is on how good the gun performs. I would take one in a heartbeat if I had the chance, as any sane person would. They are pieces of history.. And hopefully in a hundred years when paintball is all changed, ppl will still refer to you, along with bud, Tom, Tippmann... etc for all the accomplishments. Isn't that a great feeling?

That is an awesome story... someone needs to publish it in APG or something. Bud shouldn't get so much credit.. :).

Treghc
05-04-2002, 09:01 PM
Have you thought about this:

During rapid fire, there is absolutely NO difference between open and closed bolt.

Closed bolt:
When firing rapidly, the bolt moves back letting a ball in, then slams forward. Once in the forward position, it will immediately fire the paintball, the move back allowing another paintball to enter the breech. Depending on how fast you can shoot, the paintball should be propelled into the barrel as soon as the bolt even gets in the forward position.

Open bolt:
Just to get this straight with everyone, ALL GUNS THAT ARE UNDER THE SUN FIRE AT THE CLOSED BOLT POSITION. No matter what you say, it's true (with the exception of boltless markers such as the Epic).
Now since that is out of the way, here's how an open bolt marker works under rapid fire. A ball is inserted into the breech of the marker. Upon a trigger pull, the bolt is slammed forward to the forward position, only then is the air released through the bolt onto the paintball. Then the bolt moves backward, allowing another ball in.

Now think about this. Both guns let a paintball inside the breech, slam forward, then release pressurized air (or Co2 in some cases) onto the paintball to be propelled through the barrel. Afterwards, the bolt will move back again, allowing another paintball in, etc. Granted this is only rapid fire, but I do not know anyone that plays paintball by taking 1 shot per every second.

And, just to prove that all guns fire only when the bolt is at it's forward most position (well, forward enough to say that. there may be a .05" difference) I attached a picture of how a Matrix works. Hopefully now you will stop debating which one is better/more accurate/better range and finally figure out that they are exactly the same under rapid fire.

Havoc_online
05-04-2002, 10:19 PM
Well there ya go, this one post solved all our problems:rolleyes:

Blazestorm
10-26-2002, 02:54 PM
First off, let me say that I'm just a 13 year old and know nothing about science, I just know logic :D

1.) It is truly the player holding the gun. If you had both guns in a vice grip pointing in the same direction, that is much different. Back when I had my phantom I could hit stuff dead on, because I took the time to line up my shots... where as when I let my friend shoot it, took him 10 shots to hit it :P

2.) The Matrix is neither closed or open bolt... not sure where I read that but it has its own bolt system.

The reason closed bolt seems more accurate is because of the trajectory, the air behind the ball is a small burst of high pressure air. When you fire a cocker, you pull the trigger, the ball is loaded, than the next time you fire the ball is launched before the next ball can even see the breach, the ball is than loaded again, under rapid fire its the same thing, the ball is shot before the next ball is loaded, with open bolt the ball is sitting in a state where it can move around, where as with closed bolt the ball is still for that tiny little bit of a second. When the bolt goes forward , with an open bolt gun, the first ball will have a better trajectory because it is in a still state, but what happens is the bolt slams forward and launches the ball which deforms the ball and shoots it at the same time and because of this deformation air must have to give the ball a slight forward spin, which in turn causes the ball to not shoot as far. If you take a z-bodied mag and get the knob turned right it will shoot just like cockers, because it gets deformed correct? and gets the forward spin, well the zbody reverses that and creates a straight shooting ball, you can even give the ball some backspin and have a automag-flatline. Also, have you thought about when the bolt slams back into place? that has to move the gun around a bit

On the woods recball field, I would take a cocker over an emag... but on an airball field, I would take the emag over a cocker

Why? Cockers have less recoil, which allows them to shoot straighter (I never said more accurate) in rapid fire, since woods fields usually have many hills and things, the straighter the shot the better. But on a speedball/airball course I'd take an emag... why... speed and reliablity. Although i've never had a cocker other than a very old revenge crap out on me. All cockers I've shot required a little bit of timing, which I can do in a few minutes, and they were shooting perfect. With my emag on an airball field, I can shoot plenty of paint, and since the field isn't usually much bigger than 100x30, the range doesn't matter, because I play mid/front, I can pop out and shoot 4-5 shots in half a second... which with my cocker I could shoot maybe 2-3 shots in that half second.

Automags are more consistent 100% I can say that, I had a stock automag with a pure energy 48/3000 and was shooting a perfect 284-285-286, my stock cocker on the other hand with 68/3000 flatline was shooting a good 270-280-290

These are all unscientific ideas, these are my 13 year old thoughts and are all logic... Don't flame me if I sounded stupid... :)

Coaster
10-26-2002, 05:02 PM
I am not going to even mention all of your fallacies. I will just repost this:


Originally posted by Blazestorm
First off, let me say that I'm just a 13 year old and know nothing about science

Treghc
10-26-2002, 05:04 PM
first of all, a Matrix is open bolt. The way you tell an open bolt from a closed bolt is the position in which the bolt sits at when not being fired. If the breech is open, it's open bolt. If the breech is closed, it's closed bolt. the Matrix does not have it's own bolt system, because there can only be two. You can't have a half and half, and you can't have a left and right. It's either open or closed. The special about the Matrix is the spool valve design. It uses no hammer and no moving parts except the bolt.

Second, I already stated how closed and open bolts perform and act exactly the same when under rapid fire. There's so little time for a closed bolt marker to rest the bolt, then shoot, it just makes no difference. Say I'm rapid firing with a Matrix. And (just for an example) say the bolt is pushed forward, then after 0.03 seconds, air is released. Now say I were rapidly firing a closed bolt marker. The gap between when the bolt is at rest and when it actually fires may be 0.04 or 0.05. The difference is so miniscule, you will so no noticeable difference. Also, the ball you are loading doesn't just stop instantly. It still carries kinetic energy and is moving, just as an open bolt marker would.

I'm pretty sure that Tom Kaye proved that there is no deformation inside the barrel. The paintball moves without any spin, and moves without being deformed when shot through the barrel. Once it leaves the barrel, there are a lot of other variables that take place.

The Z=body is just like a Flatline. It induces back spin on the ball to carry the ball a little further. This is useless and annoying. If you tip the gun, you'll spin the ball slightly right, or slightly left. So, unless you shoot perfectly straigh, your paintball is going to go veering off in the direction of the spin.

Range is entirely dependant on the shape of the ball, the wind, and velocity. Take a marble and set it on a table. Now roll it off. Mark how far it goes. Not take another marble and roll it off too, but with more force. The extra velocity carries it further before it hits the ground. The same thing with paintballs. You shoot a ball at 230 fps, it's not going to go as far as a paintball being shot at 300fps. It's simple logic and proven physics.

As for consistency, that's not really the gun. It's more of the reg you use. On my old Matrix, the very first three shots I got were all 279. After that I got 280, 278, 280, 279... The reg is what did it. Before I had my sidewinder on, I was getting 270-290. Same thing happened with my current Cocker. After I put my Sidewinder on that, Im getting 291, 292, 291, 290, 292, 291, etc... The reg plays the biggest role, along with your paint to barrel match and quality.

I'm not flaming you in any way. I used to think the same as you, but if you sit down and actually think about it, it all makes sense. Plus, it's all been proven as well.

Blazestorm
10-26-2002, 06:53 PM
I was just saying what I thought, I guess what I thought was maybe half right isn't at all :(

Treghc
10-26-2002, 07:02 PM
I know. I didn't mean to put ya down or anything, I just stated what I know. It jut so ahppens that it contradicts with your statements.

Paladin
10-29-2002, 12:51 AM
This has really gotten very interesting and I really wish that I had the time to get into straightening out some of the missinformation getting spread here. Simply stated, there is in fact a huge difference between the operation of closed bolt and open bolt firing. Mainly in that when a closed bolt gun actually fires, everything has stopped moving and the ball is gone before the action starts to move again. Thus giving the air a solid wall behind it to push off of when propelling the ball. This is certainly not the case with traditional open bolt firing guns since the same blast of air that fires the ball is used to open the action. On the other hand, some of the electronic guns that utilize a ram instead of a spring to drive the hammer, can come close to the same interior ballistics potential as a closed bolt firing gun. A great deal has to do with the actual tuning of the gun (efficiency) as well as it's weight and type of action. A well tuned gun can be very accurate, efficient and consistent. Regardless of its method of operation.

That is all I have time for for now but I will have time to fight the flames whe I return to the US after Nov. 7. Currently in Thailand.


Originally posted by AGD
Nice discussion here guys. Yes lets say that reciprocating weight does have an effect on recoil and gun movement. Then by that thinking a heavy gun would be at an advantage because it's greater mass would move less. Do you see any accuracy difference between light an heavy markers?

AGD

ps someone measure the weight of a cocker hammer and rod and a Superbolt.

_Spork_1
11-11-2002, 08:06 PM
the warpig test that was done, is not something you can base facts off, they used stingrays, thats all, have you people seen the barrel on the sting ray? thats enough to take that experiment out of even questioning

Treghc
11-11-2002, 09:35 PM
Doesn't matter if the barrel were crap. If open bolt were indeed less accurate then closed bolt, it would show. Just like if you had a better barrel, but the spread wouldn't be so severe.

People have converted cockers into open bolt guns and have found no accuracy difference at all. In some cases, people have even experienced better consistency when their cocker was operating with open bolt.

_Spork_1
11-12-2002, 10:15 AM
y es it does matter that the barrel was crap, its unprdictble, theres to many variables to add in with the stingray test at warpig, i only see open bolt people accepting that as a test thta prooves it, even though that test was crap

billmi
11-12-2002, 11:06 AM
Originally posted by Blazestorm

2.) The Matrix is neither closed or open bolt... not sure where I read that but it has its own bolt system.


That's just marketing gobeldy gook.

Open Bolt/Closed Bolt refers to the bolt position when the gun is at rest, not at the moment of firing.

Sitting between shots, the bolt on the Matrix is open. Thus it is an "Open Bolt," paintgun.

Because there is a common belief that closed bolt guns have some sort of inherrent advantage, Air Power, manufacturers of the Vector (same designer as the Rainmaker later) said that the Open bolt Vector was a "simulated closed bolt paintgun" because it closed the bolt before firing. That's just "marketing speak" - all paintguns with a bolt close the bolt before firing, whether they are open bolt or not. Similarly, people have applied the same term to the Matrix as a way of trying to hold onto the "closed bolt superiority" idea in the face of an accurate open bolt paintgun.

See you on the field,
-Bill Mills

billmi
11-12-2002, 11:08 AM
Originally posted by _Spork_1
y es it does matter that the barrel was crap,

What problems did that barrel have, specifically?
What features of it made it "crap" compared to a "good" barrel?
What features does a barrel need to not be "crap?"

See you on the field,
-Bill Mills

billmi
11-12-2002, 11:15 AM
Originally posted by AGD
Nice discussion here guys. Yes lets say that reciprocating weight does have an effect on recoil and gun movement. Then by that thinking a heavy gun would be at an advantage because it's greater mass would move less. Do you see any accuracy difference between light an heavy markers?

AGD

ps someone measure the weight of a cocker hammer and rod and a Superbolt.

Let us not forget Tom, that unless we're talking about a single "sniper shot" in a realistic paintball situation, people are taking multiple shots, so in the case of the 'cocker the total reciprocating mass would involve the bolt, pump arm, cylinder piston and cocking block as well.

That in mind, we're talking about inertia here, not just rest mass. Inertial force is a function of both the mass of the object and it's velocity. A faster moving, lighter bolt could impart just as much instability to the paintgun in the shooter's hands as a slower moving, heavier bolt.

Similarly, the mass of the non-moving parts at velocity of 0 (ideally held perfectly still) would counteract the inertia of the moving parts, an inertial dampener if you will.

The "ideal" steady shooting platform would have a heavy receiver, with the internal moving mass as light as possible, and moving as slow as possible to achieve the needed rate of fire. Of course the heavier you make the paintgun, the harder it is for the shooter to hold steady, due to strength issues.

See you on the field,
-Bill Mills

billmi
11-12-2002, 11:19 AM
Originally posted by Apocolypse
somebody came out with a new electro kit for a cocker, which lets the marker operate in both open and closed bolt. it will be interesting to see how many people buy this upgrade just to see if closed bolt really is better.

If you are referring to the Firestorm kit for the Autococker, a technical writer reviewing it told me that the "closed bolt" mode is really open bolt, it just fires a little slower with a delay after the bolt has shut. At rest, the bolt is still open.

See you on the field,
-Bill Mills

billmi
11-12-2002, 11:24 AM
Originally posted by AGD
There is another comparison to make with the barrel jump scenario. Real handguns kick like a mule and jump several inches, by the same thinking they should not be able to hit ANYTHING! So why ARE real handguns accurate? Good Deep Blue question, answer that and you will know the answer to paintball gun kick vs accuracy.

AGD

Tom, I defy you to take an "accurate" handgun, which has a lot of kick and barrel jump, empty the clip into a target as fast as we shoot paintguns, and shoot as tight a grouping as the same style shooting with an "accurate" handgun which has little kick and barrel jump. Say, a Desert Eagle .50 vs. a nice target .22.

The "recoil" has much more to do with throwing off the second, third and fourth shots than the first.

See you on the field,
-Bill Mills

Treghc
11-12-2002, 05:47 PM
might want to change your example there, bill. Desert Deagels are gas powered and have very little kick. Unless, of course, you are implying that the .22 is the gun with more kick.

SlartyBartFast
11-12-2002, 05:54 PM
Originally posted by Treghc
Desert Deagels are gas powered and have very little kick. Unless, of course, you are implying that the .22 is the gun with more kick.

Don't know what a deagle is.:p

But, a 50 cal Desert Eagle sure does pack a punch. Haven't shot one myself (don't really want to as I don't see the point), but to check the sights on one I saw involved bracing the gun against a post to hold it steady. Makes VERY large holes in the target as well. :eek:

Nor do you want to be in the vicinity without headphones/ear protection. :eek:

Check out the rediculously overpowered handguns at: http://www.magnumresearch.com/

Bill has the right example. ;)

SlartyBartFast
11-12-2002, 06:05 PM
Originally posted by deded
It seems that this would make a closed bolt design more accurate then an open bolt design, except for at high rates of fire. I.E. The ball is pushed into the chamber and deformed, but has time to reshapen before the blast of air pushes it out of the barrel... where as the open bolt hits the ball, deforms it, and then instantaneously shoots it out the barrel, possibly not allowing the ball to re-round as quickly as the closed bolt would.

But the nastiest thing the Ball experiences is the blast of air accelerating it to 300fps in 6 milliseconds. As has been said else where, the forces on the ball once air is applied are perfectly distributed in the rear and transfered to the ball face by the paint. The ball remains round and is infact forced round by gas pressure.

The WARPIG test proved conclusively that neither system is better. COLD HARD FACT. Same gun, same barrel, same everything except bolt operation.

Now of course we have to battle the my barrel is better than your barrel myths. :D

Treghc
11-12-2002, 07:05 PM
well, slarty, I've seen one or two Desert Eagles shot and had someone explain to me how they operate and why they weren't experiencing much kick at all. Maybe it's modified or something. Hell if I know :rolleyes:

_Spork_1
11-12-2002, 09:51 PM
Originally posted by billmi


What problems did that barrel have, specifically?
What features of it made it "crap" compared to a "good" barrel?
What features does a barrel need to not be "crap?"

See you on the field,
-Bill Mills

are you from warpig?[sig]

the barrel isnt glossed or buffed on the inside, its like 4 inches long, and leads to unpredictable standards, you need at least reliable barrel, that would take some of the variables away,

also there was no reg=un predicatable consistancy
co2=unprediactable consistancy

Treghc
11-12-2002, 10:38 PM
does no one pay attention to waht I say? People have converted their Autocockers to open bolt markers. Everyone that ahs done it has reported that there is absolutely no noticeable difference in accuracy. Some of them even said the consistency was better when in open bolt. Is this not yet another example of how closed bolt is not more accurate than open or am I high again?

pbjosh
11-13-2002, 02:36 AM
A couple thoughts about reciprocating mass and recoil:

Two examples-

One, on a cocker, running the Racegun setup, turning it to Sniper Mode. The Bolt won't re-cock till the you release the trigger. SO- with this setup you can easily feel where the recoil is located if you pull- then release the trigger a bit later. By separating the actions you will see that ball being launched from the barrel causes the most recoil.

Two, I have built a marker that has a bolt that weights in at 4/10ths of an ounce. Total mass is by far the lowest in the industry. Yet there is still a noticable amount of recoil. Not from the bolt. From the ball being launched.

As for the rest, recoil affects are due to total valve action, energy used per shot, mass of the gun, and deflection angle between the barrel and the hand holding the gun. The mass of the actuating parts is small compared to the 200-300 in*lbs of energy discharged in the barrel of the gun.

Josh

pbjosh
11-13-2002, 02:56 AM
Weight of cocker componets:

Pump Arm average- 1.1oz

Cocking Rod stock- .7oz

Backblock stock- 1oz

Backblock lite- .7oz

Bolt stock WGP venturie w/ pull pin- 3.6oz

Bolt delrin- 1.5-2oz

Bolt Mutant- 1.1oz

Hammer- between 1.23oz-1.58oz/35-45 grams on average

Hammer tungsten- 2.54 oz/72 grams

Josh

billmi
11-13-2002, 09:51 AM
Originally posted by Treghc
might want to change your example there, bill. Desert Deagels are gas powered and have very little kick. Unless, of course, you are implying that the .22 is the gun with more kick.

The two times I've seen someone fire one, they bucked like a bronco.

The action of a Desert Eagle is of course not the point of the comparison.

I'll change the subjects to something I have fired, for a better comparison.

I can get better rapid fire groupings with my wife's brother's Remington 10-22 than with a friend's (he posts here occasionally, not sure if he wants to be pointed out for owning it) Barrett "Light 50" Model 82A1.

The Barret has sweet recoil dampening, but still it jumps the bipod 3-4 inches off the ground when shot. Even though I could shoot more accurately on a single shot than with the .22 (probably more for reasons of the sights and shooting style than anything else) the recoil after the firs shot means that I'd need to either wait until I'm settled back on target, or I'd shoot a wild grouping. If I'd cranked the Barret as fast as I do the .22, I'd muzzle climb and be lobbing shots over the horizon.

That's the issue of recoil, even if it's effect is after the ball has left the barrel, it's going to have an effect on the following shots.

See you on the field,
-Bill Mills

billmi
11-13-2002, 10:12 AM
Originally posted by _Spork_1


are you from warpig?[sig]


Yes, I own WARPIG.com.



the barrel isnt glossed or buffed on the inside,


By "glossed" and "buffed" I assume you mean honed and polished. You are incorrect in this statement, the barrel was honed and polished.



its like 4 inches long,


That is also incorrect, the barrel is 11" long.

I'm not sure where you got the above data about the barrel used in that test. I can't find it in the article about that test, can you please point it out to me?



and leads to unpredictable standards, you need at least reliable barrel, that would take some of the variables away,


Which components of the barrel were variable? As far as I was able to observe, it's interior finish, length, and inner diameter remained constant through the duration of the test.

I will repeat my question from earlier, what are the criteria you place for a "good" barrel? Please, not something vague, specific criteria.



also there was no reg=un predicatable consistancy
co2=unprediactable consistancy

I agree a reg would have helped consistency. You would also note, that at the time of that test regs were not commonly used in paintguns.

While the consistancy may not have been easily predicted, it was recorded, and comparable in both the control, and experimental firings. That's why the chronograph was used, and why the order of firings were swapped up to take into account changes in the pressure and temperature of the CO2 tank.

See you on the field,
-Bill Mills

Paladin
11-13-2002, 04:07 PM
SlartyBartFast [/i]

But the nastiest thing the Ball experiences is the blast of air accelerating it to 300fps in 6 milliseconds.

That is correct. Acceleration is in fact a rough experience for a paintball.


As has been said else where, the forces on the ball once air is applied are perfectly distributed in the rear and transfered to the ball face by the paint.

Yes, the air pressure is equal at all points on the rear of the ball but that only relates to the pressure.

The ball remains round and is infact forced round by gas pressure.

Not entirely true as it does not take into account the distortion of the ball as it is compressed from front to rear by the g-forces of acceleration. This causes it to tighten against the side wall of the launch tube and create friction at the sides which adds to the distortion into a cylindrical shape for at least part of its travel down the tube.

The WARPIG test proved conclusively that neither system is better.

No, that is not what it proved at all. That test only proved to me that the gun was not tuned properly to maximize the potential of true closed bolt operation. If the gun was not optimized for best results in one mode, it isn't hard to see why it would show similar results in another mode.

COLD HARD FACT. Same gun, same barrel, same everything except bolt operation.

The only "FACT" shown is that THAT gun on that day did not show a benifit to closed bolt operation. On the other hand, if the same bolt/hammer arrangement was used for both tests (closed and open bolt firing) the results would have to be the same. True closed bolt operation requires that the chambering cycle be completely seperate from the firing cycle. Bolt and hammer operating independantly. Open-bolt firing puts chambering of the round and firing it in the same move.

Now of course we have to battle the my barrel is better than your barrel myths. :

A barrel can only be "better" if it is different than the one it is being compared to and the best barrel for a "closed-bolt" firing gun may not be the best barrel for the same gun operating in "open-bolt" mode.

ezrunner
11-13-2002, 05:22 PM
The best way to fix this would be to have Larry Alexander
and crew from AKA tune a viking and an excalibur to
optimal operational condition, then test those two markers
with the same inline reg, tank, barrel, feeder, and
batch of paint.

You have two almost identical markers and this would be
a very nice test. I have not been able to get anyone from
aka to say the excal is better
than the viking or vice versa.

That interests me. I have the following observations:

Mag, with a heavier barrel shoots a tighter group.

Cocker (AKA Merlin, well tuned)
shoots as straight as i can hold it.

Bushmaster, shoots like my cocker, is faster than my mag. It has had everything
from sonic put on it, and the new circuit board and
eye from icd. I then tuned it.

The sad thing is, all of the markers hit well, group well,
and are good 'guns. I don't know why I have all of them.

If you have a marker, tbe best upgrade is to buy paint
and practice with your marker till you can hit a pod across
the field in less than 3 shots
snapping out of a bunker.

The mag will do it, my spyder even did it.

BTW - My favorite 3 people in paintball:

Glenn Palmer (for his automagic pump)
Tom Kaye (for the mag)
Larry Alexander (for all things AKA)

My conclusion has been that the cockers I owned were very
fun to tinker with and were easier to shoot more accurately
than my mag. I believe part of this had to do with the
movement and impulses on the marker upon firing.

My mag is a tank and cannot be
stopped (so it seems).

My bushy is a great gun, but it took a lot of money to make
it that way. I would buy an impulse w/ vision if I had
to start over again.

If I could only have one paintball marker
from now on. It would be a hard choice between an
AKA bodied cocker w/ eclipse hinge, and the emag.

-rob

SlartyBartFast
11-13-2002, 06:36 PM
Originally posted by Paladin

On the roundness of paint in barrels:

Not entirely true as it does not take into account the distortion of the ball as it is compressed from front to rear by the g-forces of acceleration. This causes it to tighten against the side wall of the launch tube and create friction at the sides which adds to the distortion into a cylindrical shape for at least part of its travel down the tube.

Sounds all scientific and even believable. But the contents of a paintball are largely uncompressable. The gas pressure at the back of the ball is equally distributed and imparted on the uncompressible liquid fill which in turn pushes on the front of the shell. This all dictates that the paintball remains round. Tom Kaye has claimed high speed photography not showing deformation. I tend to beleive him, and his results coupled with the nature of the forces seem to point to a round paintball.

But that's all beside the point. What's the magical difference between open and closed bolt? In the barrel the forces are identical.



On the WARPIG experiment:

No, that is not what it proved at all. That test only proved to me that the gun was not tuned properly to maximize the potential of true closed bolt operation. If the gun was not optimized for best results in one mode, it isn't hard to see why it would show similar results in another mode.

What's the magical optimisation that will help closed bolt operation? While I respect what PPS does with markers, valves, and regulators, no hint is given here as to what magic the elves are supposed to be accomplishing. What optimisation should have been done? Why shouldn't the same optimisations be done to the open bolt?


The only "FACT" shown is that THAT gun on that day did not show a benifit to closed bolt operation. On the other hand, if the same bolt/hammer arrangement was used for both tests (closed and open bolt firing) the results would have to be the same. True closed bolt operation requires that the chambering cycle be completely seperate from the firing cycle. Bolt and hammer operating independantly. Open-bolt firing puts chambering of the round and firing it in the same move.

If you read the test descrition it seems to me the firing was separate from the chambering. In fact it would seem the gun was operated as a 'bolt action'. Meaning that any claims this wasn't 'TRUE CLOSED-BOLT' are somewhat far-fetched.

What's the magical rest time that a ball needs to recover from the 'abuse' from the bolt? Leading to the question of at what point does closed bolt, if you beleive it has an advantage, become the same as open-bolt?

Where's the proof that the bolt deforms the ball so as to affect consistency?


A barrel can only be "better" if it is different than the one it is being compared to and the best barrel for a "closed-bolt" firing gun may not be the best barrel for the same gun operating in "open-bolt" mode.

<LOL> What's the magical force that makes the barrel requirements different? What are the differences that do make a barrel better?

Nomad
11-13-2002, 09:44 PM
Then perhaps the next Open bolt vs Closed bolt test done:

1) With an Autococker with the Firestorm Kit equipped on it.

2) Using an aftermarket barrel, perhaps an Aradus as it can be adjusted for multiple bores, thus having a better chance for paint to barrel match.

3) Using a HPA tank and another regulator (perhaps a Palmers Stabilizer and one of those AGD Flatlines. We're taking one shot at a time, shoot-down probably not a problem).

4) Making the test in indoor conditions, to reduce the chance of wind being a factor (don't think wind can be completely eliminated in any condition).

5) Have the target at about 30 to 40 feet, to simulate normal shooting distance in a game.

6) Use a good quality paint. (No duh....)


That's my suggestion.

SlartyBartFast
11-14-2002, 12:14 PM
Originally posted by Treghc
does no one pay attention to what I say?

Standard reaction to reasoned logic attacking a religiously held belief.:D

SlartyBartFast
11-14-2002, 12:22 PM
Originally posted by Nomad
Then perhaps the next Open bolt vs Closed bolt test done:

Sounds like a fine setup.:)

The only thing is that besides gut feeling and prejudices, no one has yet come up with any real reason to discredit the original test.

If there were any real reasons I'd like to hear them and be shown some proof that the reasons are valid.

Beyond Magic and Elves, the following equation will be true: Same paint to barrel match, in a decent barrel, same exit velocity, same result.

The only thing that will affect the 'accuracy' is the hand pulling the trigger and pointing the marker.


Originally posted by ezrunner
The debate is BS open/closed/electro
The game is not in the gun, it is in the player.

What he said!:D

But it takes REAL balls to go up against Electros with a Splatmaster.:cool:

Paladin
11-14-2002, 02:10 PM
Originally posted by Nomad
Then perhaps the next Open bolt vs Closed bolt test done:

1) With an Autococker with the Firestorm Kit equipped on it.


Getting an accurate evaluation of the difference between closed and open bolt firing will depend on whether or not the hammer and bolt function independantly or connected together and functioning in unison. If the bolt and hammer are not connected and moving independantly, true open bolt firing is not being accomplished. Electronic timing of the bolt movement and hammer release can present a miss-conception of open bolt operation.


[i]
2) Using an aftermarket barrel, perhaps an Aradus as it can be adjusted for multiple bores, thus having a better chance for paint to barrel match.
[/B]

One of the biggest considerations for the consistency and accuracy of a barrel on a closed bolt firing gun is a provision for making sure that the ball stays in contact with the face of the bolt when the ball is chambered so each ball is fired from the exact same location in the barrel. A ball fired from even a little bit forward of the bolt will generally be a bit lower in velocity than one fired from a position that is tight to the face of the bolt. That is the reason that the barrels on all PPS markers (all closed bolt firing guns) are honed to an eliptical shape in the bore and have a containment system at the rear of the barrel (called the "wedgit" system) to insure consistent positioning of the ball when it is fired.



[i]
3) Using a HPA tank and another regulator (perhaps a Palmers Stabilizer and one of those AGD Flatlines. We're taking one shot at a time, shoot-down probably not a problem).
[/B]


4) Making the test in indoor conditions, to reduce the chance of wind being a factor (don't think wind can be completely eliminated in any condition).


[i]
5) Have the target at about 30 to 40 feet, to simulate normal shooting distance in a game.
[/B]

Stretch that distance out to 60 to 100 feet and you will more easily be able to measure the difference in shot pattern. Especially if the gun(s) are fired from a vise and take the shooter out of the equation.


6) Use a good quality paint. (No duh....)


That's my suggestion. [/B][/QUOTE]

Paladin
11-14-2002, 02:22 PM
Sorry, but I don't deal in Magic or elves.

If you accurately define the difference in operation between firing from the open bolt position and firing from the closed bolt position, you will minimize your confusion.


Originally posted by SlartyBartFast


Sounds all scientific and even believable. But the contents of a paintball are largely uncompressable. The gas pressure at the back of the ball is equally distributed and imparted on the uncompressible liquid fill which in turn pushes on the front of the shell. This all dictates that the paintball remains round. Tom Kaye has claimed high speed photography not showing deformation. I tend to beleive him, and his results coupled with the nature of the forces seem to point to a round paintball.

But that's all beside the point. What's the magical difference between open and closed bolt? In the barrel the forces are identical.



What's the magical optimisation that will help closed bolt operation? While I respect what PPS does with markers, valves, and regulators, no hint is given here as to what magic the elves are supposed to be accomplishing. What optimisation should have been done? Why shouldn't the same optimisations be done to the open bolt?



If you read the test descrition it seems to me the firing was separate from the chambering. In fact it would seem the gun was operated as a 'bolt action'. Meaning that any claims this wasn't 'TRUE CLOSED-BOLT' are somewhat far-fetched.

What's the magical rest time that a ball needs to recover from the 'abuse' from the bolt? Leading to the question of at what point does closed bolt, if you beleive it has an advantage, become the same as open-bolt?

Where's the proof that the bolt deforms the ball so as to affect consistency?



<LOL> What's the magical force that makes the barrel requirements different? What are the differences that do make a barrel better?

pbjosh
11-14-2002, 02:56 PM
My thoughts and opinions-

This is my simple, no science added, total WAG, and I know that those things are not appreciated in Deep Blue.

I personally thought, as long as the valve is consistant and areas such as barrel and paint are decent, that the only other factor that could affect accuracy in the feilds of Open vs Closed bolt is the movement of the ball as the air is applied to it.

In-accuracy is from a ball incurring to much spin. You want to have a small, slight spin on the ball, just to counter static boundry affect issues (sorry to add science to a WAG), but too much spin pulls it to the side it rotates against.

Now, if a gun incurrs pre-spin on the ball, so that the ball already has spin (such as forward or 'down' spin) as the air hits it then the related spin is increased (according to this WAG.) This would be influenced by guns that had loose breeches, and had a fast cycling bolt. If the ball was able to stop completely before the air hits it, I would think that the you would loose the incurred spin. Or if the gun has a tight breech, so that the ball spin is minimised. Also for guns that had breeches that were too tight, or a barrel transition point that could also add to the spin.

But most of this is a guess. I am most likely wrong, and even not close in any manner. DO NOT TAKE THIS AS TRUTH! And there would be quite a few other issues, such as valve type and such.

I do know of a guy who has a very clean closed bolt Angel. It can be ran either Open of Closed by turning the bolt, with no difference in performance besides that. When he gets finished with it, he can do some true Open vs Closed with a little more of a top of the line gun (sorry Bill!), one that also has had a history with its accuracy and range.

Please feel free to pick this apart, thats why I dropped it here.

Josh

ezrunner
11-14-2002, 03:22 PM
Paladin (all reverence due):
I am not arguing one is better than the other, I have this to pose.

If say a lapco autospirit barrel, and paint that mic's out to .688 were used.
That should ensure a tight fit in the breech for each shot.
We also assume the ball is pushed into the breech of the
barrel on this marker before air
is introduced.

What does the small amount of time that the bolt is at rest
before the valve is openned buy us?

I honestly think the debate will never end, and that marker a can be shot
as well as marker b with the
right setup. This is just
a clarification issue I think
could be interesting.

Thanks for any input.

-rob

bjjb99
11-14-2002, 03:30 PM
Would a pump-action Phantom with an autotrigger be an appropriate open bolt equivalent? You can cock the marker, hold down the autotrigger, and move the pump forward to fire, thus firing from an open bolt position. If you controlled the pump arm with a pneumatic ram (for more consistant shot to shot pump motion), you could operate the Phantom in either open or closed bolt mode simply by choosing whether the trigger is continually squeezed (autotrigger "open bolt mode") or only squeezed after the bolt is in the forward position (normal "closed bolt mode").

Bench mount the Phantom, clamp the trigger down, and just cycle the pump. Measure each shot's velocity. Measure the shot grouping at a fixed distance. Remove the trigger clamp, install a solenoid to move the trigger (so no hands touch the bench mounted marker during firing), and repeat the velocity and grouping test. Repeat the test as many times as you like at different target distances.

Just a thought for a reasonable open/closed bolt testbed. Feel free to hurl rotten fruit my way if you see fit to do so. ;)

BJJB

SlartyBartFast
11-14-2002, 06:03 PM
Originally posted by bjjb99
Would a pump-action Phantom with an autotrigger be an appropriate open bolt equivalent?

Yet another good suggestion for a test. But I guess Palladin will have something to say about 'true-open-ness'.

SlartyBartFast
11-14-2002, 06:15 PM
Originally posted by Paladin
Sorry, but I don't deal in Magic or elves.

If you accurately define the difference in operation between firing from the open bolt position and firing from the closed bolt position, you will minimize your confusion.



With all due respect you don't get away with blithe comments in Deep-Blue (or maybe you do as you refuse to give out any technical ideas). If I'm confused it's because you're offering no new information. How about some meatier explainations?

What can be more 'true-closed bolt' than bolt action? That was how the Stingray was fired in the test.

Sounds to me that you're just arguing tiny semantics (and millionths of a second) to try a maintain a point that puts your own products in a better light.

Which is really unfortunate as there is no doubt about it, your guns are good and amongst the best. But you're not providing much in the way of proof or substance here.


Originally posted by ezrunner
What does the small amount of time that the bolt is at rest before the valve is opened buy us?

And that's the million dollar question. At what rate of fire does open-bolt equal closed-bolt if you are to believe one has an advantage over the other? Under rapid fire, you're talking milliseconds between the mythical stop and stabilisation of the ball and the injection of gas.

Still waiting for some kind of proof that once jammed into a correctly sized barrel how any of the theorising of bolt/ball dynamics really has any effect.

A well tuned cocker (closed-bolt) and an XMag (open-bolt), both with the same barrel (as both are cocker threaded and use detents), shooting the same velocity, will both perform identically.

AGD
11-14-2002, 10:30 PM
And the debate rages on..... I must say that this debate is much more enjoyable here in Deep Blue than other places where it ends up "just because!"

I would like to ask this learned group, if the debate is over which one is "better" what magnatude of "better" does it have to be to constitute proof?? If a closed bolt shoots one ball out of 1000 more accurately does that count? How about 1 in 100 or 1 in 20??

In astrophysics this is asked all the time "how do you know you really detected something?" In that field they do it statistically with either a 2 sigma or 3 sigma requirement for a clean believeable detection of difference.

Some of you must know about statistics here and understand what a 3 sigme detection means. I would sugest you argue the right protocall for a test in hopes that someone will actuall do it and put this to rest.

AGD

nippinout
11-15-2002, 12:48 AM
Statistics, eh?

You question the importance of only having a few shots more accurate than open bolt.

But all of this is quite moot.

A sphere is a sphere is a sphere.

Many people have argued that the Warpig test used low-end equipment for it's open/closed bolt test. I whole heartedly agree.

But as in every test, your results must be repeatable and you must minimize your variables.

Why weren't nylon balls used? One might argue that results from using nylon would not matter because we do not use nylon balls on the field. But, when we can't have trials that aren't exactly the same, you throw the hypothesis out the window.

Now if we talk about 3 sigma, that's a whole other can of worms.

For those unfamiliar with statistics, sigma is a notation used so we can estimate the percantage of a population within a range of the median determined by sigma.

Tom, in your example of having 1 out of 100 shots more accurate than open bolt, if it is important enough. As a marketing standpoint, having even 1 out of 1000 will have a large amount of people shelling out for a new gun. As a functional standpoint, no. So where do we determine importance? If it is functional! :)

Three sigma is quite a large percantage of a population. Two sigma is also quite large.

Jebus, astrophysics has crazy amounts of assumptions and approximations. My physics TA was a grad student in astrophysics and told us how they make calculations where they round off a few hundred billion miles and still be okay.

Let's use our handy dandy Paintball Trajectory Calculator at http://home.attbi.com/~dyrgcmn/pball/trajectory.html

At 300 fps, we have the ball terminating at a range of 118.7 feet, .427 feet high, and 138.1fps.

At 310 fps, we have the ball terminating at a range of 121.4 feet, .450 feet high, and 140.1fps.


At 290 fps, we have the ball terminating at a range of 115.9 feet, .404 feet high, and 136.0fps.

I have no clue why the ball terminates with velocity and elevation, but let's take this data as is.

Let's say our target is some dude at 118.7 feet away from us. He's sticking out his bum out the side of his bunker. At 300fps, we got him. At 310fps, the ball travels less than 3 feet more and .23 feet higher in elevation. Basically, we got him at this range too. At 290 fps, we have a similar situation where the target is large enough to tag his bum.

I took some liberty in the assumption of the ranges of the 3 velocities hitting him, but the end elevation are within .046 feet in a range of 5.5 feet. That target area is a pretty tight one.

So with a velocity fluctuation of +/-10fps, we have a pretty accurate gun. And this is for a target over 100 feet away. Would you be happy with a gun that shoots +/-10fps? It's pretty damn accurate, but it isn't a selling statistic.

So how accurate is your gun? As accurate as your shot to shot accuracy. I guess I should be asking how consistent is your gun. Consistency is key. Paintballs aren't accurate shot to shot. Once again, a sphere is a sphere is a sphere.

When a noob asks you what is the most accurate gun, you don't tell them which gun, but rather just to get a gun that will make them happy and a freak kit (Or a bore that fits their fields paint best).

I say we make a new discussion about the Advantage shell. It has a roughed up texture as compared to the other glossy smooth shells. And the stuff just SMELLS like my grandma deep frying fish in a wok of dumpster juice.

So in conclusion, I believe that there is little benefit to accuracy from improving shot to shot accuracy. The only PRACTICAL benefit I see in improving consistency is in tourney ball. A consistent gun will allow you to run a velocity as close to 300fps possible without going over and getting penalized for hot shots.

Your gun isn't accurate. It's accurate enough. :)

SlartyBartFast
11-15-2002, 11:50 AM
Originally posted by nippinout
Your gun isn't accurate. It's accurate enough. :)

Too True!:D

If we really want to look at accuracy statistically, I already proposed a method for testing barrel length differences in another thread.

http://www.automags.org/forums/showthread.php?s=&postid=513906#post513906

But to say neither open nor closed-bolt makes a difference we're still debating those that would have us beleive there is some magical/unexplainable force working on the ball after it leaves the barrel. But they contend that it can be optimised for.

pbjosh
11-15-2002, 12:56 PM
Personally-

I think accuracy, or inaccuracy, itself needs to be looked at. What causes problems, what would make one shot, not gun, more accurate than another.

Alot of people have taken the easy way out and said "all the guns firing at the same velocity shoot the same distance" but don't think that is right. Look at the Flatline barrels. That alone breaks the statement all to bits.

Look at a baseball pitcher. He can throw a ball at the same speed, but with incurred spin on a ball he can control the distance and do, well, if I could make a gun that shot like a baseball pitcher..............

With every ball, the spin it has is the ENTIRE issue with accuracy. So, if a gun, barrel, ball, magic elves, can make the ball spin at the right rate, then you can have the range and accuracy inherent in the system.

I think that some gun systems add an amount of bad spin. As I stated above some of the reasons, what needs to be put down first, above ALL the velocity issues, is SPIN.

Spin is the issue at hand, not velocity, not Closed Bolt or Open. If you can have the right about of spin you have good range and accuracy. If you have bad spin, then you don't have either.

The arguement of velocity = range does not work when shooting a round projectile. Because spin is going to affect both portions of it.

Saying the range is totally a factor of velocity puts you in the "Earth is Flat" group.

Josh

hitech
11-15-2002, 01:49 PM
Originally posted by pbjosh
Alot of people have taken the easy way out and said "all the guns firing at the same velocity shoot the same distance" but don't think that is right. Look at the Flatline barrels. That alone breaks the statement all to bits...
Saying the range is totally a factor of velocity puts you in the "Earth is Flat" group.
I think what "most" of us say/mean is that without spin, guns firing at the same velocity shoot the same distance. Sometimes we just get lazy and leave out the "without spin" part. ;) As far as I know, NO ONE has EVER proven that anything other than spin (and velocity) affect distance and accuracy of a standard paintball.

Paladin
11-15-2002, 04:30 PM
Your gun isn't accurate. It's accurate enough.

[QUOTE]Originally posted by SlartyBartFast


Too True!:D


I contend that most of our 'guns are plenty accurate considering the projectiles that we are dispensing. Someone stated in a post earlier that "a sphere is a shpere is a sphere" and that is true but I haven't seen many paintballs that are actually a true sphere. Most every paintball that I have seen and/or measured is a bit larger around or across the seem than it is when measured around or across the poles of the ball. It is also true that paintballs are filled with a material that is generally accepted as a "non compressable liquid" . Howerever, that liquid is contained in a relatively flexible container which is susceptable to distortion from the influance of the g-forces applied during the process of acceleration. Thus, when when acceleration begins, the flexibility of the shell allows the ball to tighten against the bore of the barrel and become somewhat cylindrical in shape. You can prove this out to yourselves with a very simple demonstration. Place a clean, unmarked ball in a barrel that you can blow it through with your own breath fairly easily. (a common "test" for proper bore sizing) Now blow the ball through the barrel and catch it in a soft cloth so you can inspect it closely (under magnification). After moving the ball through the barrel you will be able to see a small skid mark left on the surface of the ball; usually at two points near the seem of the ball. Now take that same ball and shoot it at game velocity through the same barrel at a bed sheet or similar hanging soft cloth that will catch the ball instead of breaking it on impact and again observe the size of the skid-mark left on the ball as it went down the barrel under pressure. You will see that the abount of shell that comes in contact with the sides of the barrel is significantly larger than when moved through the barrel with higher acceleration and g-forces. Now, the simple fact remains that the ball could not show a wider track on it unless it distorted enough to tighten the ball against the walls of the tube it is being pushed through. As the ball tightens and seals against the bore it has no choice but to become shorter in length, aka distorted by the forces of acceleration. Though not supported by a set of scientific calculations, the above demonstration and maybe a little basic comon sense, should prove to at least some of you that a paintball has to go through a lot of changes during the process of getting launched effectively. The trick to "effective" launching of a paintball is to understand that what goes on inside the barrel can and does effect what goes on shortly after the ball leaves the barrel. Internal ballistics do in fact influence external ballistics.
The most noticeable effect of improper propulsion characteristics (or tuning) is the amount of muzzle blast that can and does impart influence to the flight of a paintball AFTER it leaves the barrel. In short, the FACT of the matter is: if a mass of air blows past the not so round and somewhat flexible sphere after it has left the confines of the barrel, it can and does affect the flight of the projectile. Therefore, proper tuning and/or other means to control and minimize the muzzle blast are paramount to maximum effective range and accuracy. Proper tuning seeks maximum efficiency which in turn minimizes the effects of muzzle blast. You can also cut down on the muzzle blast effect with the application of a muzzle break to relieve and disperse excess air before the ball leaves the confines of the barrel. A short barrel with a long muzzle break (as is the case with many or most barrels these days) can and does help to compensate for an inefficient shot. That's why I started putting muzzle breaks and vented barrels on guns back in 1987.
In reference to Tom's high speed photography of many years ago, I seem to recall that was to address the condition of the ball at the point of or after leaving the barrel.
Tom, please correct me if I am wrong here. Also, is it possible that we can see some of those pics for ourselves?


If we really want to look at accuracy statistically, I already proposed a method for testing barrel length differences in another thread.

http://www.automags.org/forums/showthread.php?s=&postid=513906#post513906
[/B]

Statistics are only a guide, reality is definative.
That sort of testing was done many years ago only I did it with .5" increments of barrel length and did it with and without adjusting the valve output to accomodate the varying barrel lengths. My testing was also done at a fixed distance of 100 feet to minimize variables. The point of my tests was to establish what barrel length was needed to achieve the proper balance of efficiency and accuracy. Since the standard power source of the day was 12 gram cartridges, efficiency of the shot was very important and the first thing I noted was that as efficiency was improved, the size of the shot pattern on the target got smaller and the second notable point was that as velocity is increased, the shot pattern got larger. I also noted that a barrel that is too long suffers many of the same shortcomings in efficiency and consistency as one that is too short. Mainly due to the varibles of the painball's shape, size and weight.

In your test procedure you start with an 18" barrel and chrono the gun to 300 fps. My question is; when you cut the barrel down by 2" do you also adjust the pressure in the dump chamber to retain 300 fps or do you log the results of only cutting the barrel ? If you adjust the pressure to maintain a given velocity, you are effectively "tuning" the gun to suit the barrel; right ? If you start with an 18" barrel at 300 fps and start cutting the barrel down without making changes to the pressure or volume of gas being used to launch the ball, you should find that velocity will climb and the shot pattern will rise and get larger on the target for the first few cuts. Will you be able to understand the results ? Will you know why cutting a barrel down can often result in an increase in velocity? Are you sure that 300 fps is the best for testing since acceptable velocity limits seem to be coming down to 280-285 going on and 300 coming off? Also, for such testing purposes, you will find that the size of the shot pattern and whether the velocity goes up or down with each subseqant change will be the leading criteria for evaluation. Better effective range will only be indicated when the shot group rises on the target without changing anything other than the barrel.



But to say neither open nor closed-bolt makes a difference we're still debating those that would have us beleive there is some magical/unexplainable force working on the ball after it leaves the barrel. But they contend that it can be optimised for. [/B]

Since it seems obvious that I cannot "prove" to you that there is a benifit to closed bolt firing of a paintball (that is as opposed to traditional open-bolt firing as found in most blow-back operated guns) maybe you should present some substantiated facts that "prove" me wrong. However, you will have to change my mind and not just throw out a bunch of adversarial inuendo that would require the writing of several books to address effectively. Please keep in mind that I have a bit over 40 years of experience in dealing with guns and ballistics (internal and external ballistics) in general and nearly 20 years and tens of thousands of hours invested in finding and understanding the best way to get a paintball to go where and when I need it. On the other hand, I don't have a scientific or debating backround so I have to deal with what I know and what I see. No magic, no little elves no guessing; just a plain and simple reliance on reality.

pbjosh
11-15-2002, 04:38 PM
Hitech-

half this thread is not about open or closed bolt, it is about people saying the guns will shoot the same distance. Spin is NOT included.

Actually I think, maybe not in this forum, but others, that it is something forgotten more than not.

And crucial to the Open vs. Closed debate.

We have gotten the knowledge that the gun will shoot the same distance shooting a ball the same speed, but, for the most part, people are still saying "Angels will shoot just as far as a Shocker because the ball leaves the barrel at the same speed." In fact a good chunk of the better brains this sport has.

And that just isn't correct. Some guns do shoot a bit further. Paint just flies into the ground when you shoot other guns. This is the way it is.

Why? Spin. Which is inherent in some guns. And the true center of this debate, NOT velocity.

Josh

pbjosh
11-15-2002, 04:44 PM
Glen,

That is a very disturbing picture.

Josh

Paladin
11-15-2002, 04:58 PM
Sorry. I did not think it would be offensive to anyone.

it has been deleted from my post.

SlartyBartFast
11-15-2002, 05:42 PM
Originally posted by pbjosh
Personally-
Alot of people have taken the easy way out and said "all the guns firing at the same velocity shoot the same distance" but don't think that is right. Look at the Flatline barrels. That alone breaks the statement all to bits.
...

Saying the range is totally a factor of velocity puts you in the "Earth is Flat" group.

Josh

I think you'll find that the complete statement is:

"All markers shooting the same velocity shoot the same distance, except for the flatline barrels or Z-body Automag."

That's what the position has been in the umpteen other debates on this topic.

On a side note, my colleague who is heavily into firearms and shooting says that the only advantage between open and closed bolt action in a real firearm is for first shot precision/accuracy. But bolt them down to counteract the inertia of the bolt (which on an UZI approaches a couple of pounds) on an open bolt and there's no difference.

pbjosh
11-15-2002, 06:20 PM
Glen,

I found the pic a bit disturbing, but it was really funny! It didn't offend at all.

Post it back up, I don't care-

Slarty,

You are missing something basic.

ALL gun induce spin. Some merely direct it.

Since all guns induce spin, some induce it more than others.

Guns that induce more spin are less accurate.

If a gun induced more forward spin it would be less accurate and have less range.

Hence, guns that induce the least spin are more accurate, and will have better range.

If a ball rolls into a barrel, incurring alot of forward spin, when it is fired it this will cause more forward spin, equalling less range.

Like I said, spin is in EVERY ball shot. Less spin means a more accurate gun.

Since EVERY gun induces spin, the factors of range are induced IN the gun, and are not SIMPLY a factor of velocity.

Josh

_Spork_1
11-15-2002, 08:27 PM
Originally posted by billmi


Yes, I own WARPIG.com.



By "glossed" and "buffed" I assume you mean honed and polished. You are incorrect in this statement, the barrel was honed and polished.



That is also incorrect, the barrel is 11" long.

I'm not sure where you got the above data about the barrel used in that test. I can't find it in the article about that test, can you please point it out to me?



Which components of the barrel were variable? As far as I was able to observe, it's interior finish, length, and inner diameter remained constant through the duration of the test.

I will repeat my question from earlier, what are the criteria you place for a "good" barrel? Please, not something vague, specific criteria.



I agree a reg would have helped consistency. You would also note, that at the time of that test regs were not commonly used in paintguns.

While the consistancy may not have been easily predicted, it was recorded, and comparable in both the control, and experimental firings. That's why the chronograph was used, and why the order of firings were swapped up to take into account changes in the pressure and temperature of the CO2 tank.

See you on the field,
-Bill Mills

alright i used my friends sting ray before it was inaccurate in my mind, saw the balls going all over the palce, and the paint to barrel match was right

didnt know abonut the swaping to get the same fps for both clsoed and open

my thoughts, this is never going to be prooven either wayt, even though i slightly defended closed bolt with argueing the warpig.com test i do not think that it[closed bolt] is more accurate or less accurate or the same, i have no real results that will make my mind change at this moment, even though im neutural i still wont accept the stingray test as proof, too many varaibles to put in, (bad barrel(try a cp or something along those lines) ( bad gun, yes tons of people think "all guns shoot the same accuracy" but i think that some guns are better than others , hense the price marks

too tired after wrestling practise, proboly some typos and errors in m yrepsonse

billmi
11-15-2002, 09:50 PM
Originally posted by _Spork_1

(bad barrel(try a cp or something along those lines) ( bad gun, yes tons of people think "all guns shoot the same accuracy" but i think that some guns are better than others , hense the price marks


I'll ask again.

Please define a "good" barrel, and what makes a barrel "crap." Since I don't believe that Dan at CP has magic dust to sprinkle on his barrels that make them good simply because they are CP barrels, how can we decide if a barrel is "good" or "crap" for a test? What are the criteria?

Same question for the paintgun.

See you on the field,
-Bill Mills

billmi
11-15-2002, 10:01 PM
Originally posted by Paladin

Now, the simple fact remains that the ball could not show a wider track on it unless it distorted enough to tighten the ball against the walls of the tube it is being pushed through. As the ball tightens and seals against the bore it has no choice but to become shorter in length, aka distorted by the forces of acceleration.

I believe such wider "tracks" on the ball could also be achieved by the ball pitching and yawing during its travel down the barrel. Many have taken it as a given that the ball will face some rotation when fired - if the ball does in fact distort to this semi-cylindrical shape, such rotation would not be possible. Thus "hook" shots caused by a yawing spin couldn't happen.

I've had a look at some of the high speed video and stills Tom has taken of balls fired through a clear barrel (some is included in the Automag RT video.) If the balls are distorting, it is too insignificant to see in the photographs. An important question to which I hope Tom can supply an answer is, where those done with gelatin paintballs, or with Perfect Circle paintballs, which have a more rigid plastic shell?

Please also note, I will happily disagree with Glenn on theory or interpretation of the results of a test or experiment, but this in no way means I don't respect his viewpoint. There are a lot of people in the industry that will support a certain theory regardless of its validity, simply as a means to market their product. Basically they have a product, and whip up a theory to explain to you why it's the best in the world and you need to buy it. Glenn on the other hand, has used his theories of paintgun operation to build quality products, and is one of the few manufacturers/customizers to understand the concepts of old world craftsmanship.

See you on the field,
-Bill Mills

AGD
11-16-2002, 05:02 AM
The balls in the video were run of the mill gelatin.

You guys keep thinking that spin has something to do with accuracy, I would like you to prove that with something other than conjecture. Linking baseballs to paintballs doesn't cut it.

AGD

billmi
11-16-2002, 10:50 AM
Originally posted by AGD
The balls in the video were run of the mill gelatin.


That's what I thought, good to hear it confirmed.



You guys keep thinking that spin has something to do with accuracy, I would like you to prove that with something other than conjecture. Linking baseballs to paintballs doesn't cut it.

AGD

I would think the most straightforward way to document its effect would be with two-tone paint, and high speed photography as you have done.

From anecdotal evidence....

The Tippmann Flatline generates spin that has a noticable effect on the trajectory of the paintball. If the Flatline is turned 90 degrees on the roll axis and fired, the ball will lob like a normal paintball trajectory, but will hook to the left or right (depending on the direction in which the 'gun was rotated).

This hooking left or right is a behavior also sometimes seen (though not as severe) when firing paintballs out of a paintgun without any spin/no-spin design features.

Comparing this and photography AGD has taken of balls that don't spin in flight and seem to "wander" randomly in the vertical and right-left axes as they travel to target, it is reasonable to believe that a yawing spin can cause a ball to drift to the left or right of the intended target, and a pitching spin will create a vertical drift vector.

Certainly, more detailed experimentation would prove or disprove this hypothesis.

As for linking baseballs to paintballs, that brings up one of my pet peeves....

The next time someone talks about how paintballs can't maintain a spin because they are full of liquid, and "proves" it by the fact that a raw egg won't spin on a table but a hardboiled one will, throw an egg at them, because they want to play egg-ball. Then spin a paintball on the table and see how it does, and explain to them that paint fill is thicker, and doesn't have an inner sac connected to the shell with elastic like tendons.

See you on the field,
-Bill Mills

Paladin
11-16-2002, 11:51 AM
Originally posted by AGD
The balls in the video were run of the mill gelatin.

Tom, I was going to ask the same question that Bill did but it seems to me that you did the high speed photography thing before you got started on the PC balls project. Is my memory serving me correctly ?
Also, what is your take on the idea that a paintball squats a bit against the force of acceleration and tightens against the bore when it is fired ? Don't we need the ball to tighten and seal against the bore if we are to expect any kind of consistency?


[i]

You guys keep thinking that spin has something to do with accuracy, I would like you to prove that with something other than conjecture. Linking baseballs to paintballs doesn't cut it.
AGD [/B]

Again, I don't know how to "prove" it but it has been my experience that the more spin seen on a ball in flight, the larger the shot group will be on target. Here, we strive to get our guns to shoot a "nuckle ball" with no spin at all. The actual flight of the ball looks a little erratic at times but they are more likely to be in a tighter group on target.
In the old days of single colored balls, it was hard to see what was going on but when we got paint with contrasting colors in/on the shell, it was much easier to see the results of our tuning process with just a few shots. If we see much spin on the ball in flight, the gun goes back to the bench to find out why and correct the problem. Oddly enough, we have found that we could minimize the amount of spin being imparted on the ball by insuring that the air flow through the valve, air passages and bolt was "clean" fast and non turbulant. Sort of like the concept of "porting and polishing" the heads on a high performance engine. Quite often, we can drastically improve on shot-to-shot consistency, efficiency and and accuracy with just a minor correction to the shape or condition of an air passage between the valve and the face of the bolt. I've seen numerous instances where 5 seconds with a Dremel tool to champher one corner of an air passage can improve velocity by 20-40 fps; which in turn means that the shot will be more efficient, the ball will get up to speed quicker, more consistent and generally more accurate.

billmi
11-16-2002, 12:51 PM
Originally posted by Paladin

I've seen numerous instances where 5 seconds with a Dremel tool to champher one corner of an air passage can improve velocity by 20-40 fps; which in turn means that the shot will be more efficient, the ball will get up to speed quicker, more consistent and generally more accurate.

Glenn,

In a previous post you said the open/closed bolt accuracy test did not show a difference between bolt position because the test gun was not tuned for optimal closed bolt performance.

Would it not be a possibility that it's the tuning that is optimizing efficiency and consistency in the gun setup, rather than bolt position that has provided the improved performance in your experiences?

Se you on the field,
-Bill Mills

pbjosh
11-16-2002, 01:17 PM
AGD-

Proving spin on the ball affects accuracy? That is a given. The balls spin when they leave the gun. All of them do.

Conjecture? Magnus affect, boundary layers and all that:

http://www.geocities.com/k_achutarao/MAGNUS/magnus.html

http://www.lerc.nasa.gov/WWW/K-12/airplane/bball.html

http://www.lerc.nasa.gov/WWW/K-12/airplane/beach.html

http://landau1.phys.virginia.edu/classes/311/notes/aero/node2.html

http://www.newscientist.com/lastword/article.jsp?id=lw387

And that is just the TIP of the iceberg. We are still dealing with a ball, which at 200mph makes for alot of interesting affects moving through an atmosphere. Spin is the entire issue for accuracy and range.

Bill-

As for the egg reference, tell them to throw an egg. Does it stop spinning? I can't throw an egg far enough for it to stop spinning before it hits, but that might be me. It does slow down...........hmm...........time for testing?

Glen-

What you were doing with tuning the valve is what I was trying to do with the 'Shiva' project. I found my valve is still a bit to harsh at 160psi, but the effeciecy and accuracy are both very good. A clean tuned port makes for an accurate gun in my opinion.

Josh

Paladin
11-16-2002, 02:29 PM
Originally posted by billmi


I believe such wider "tracks" on the ball could also be achieved by the ball pitching and yawing during its travel down the barrel. Many have taken it as a given that the ball will face some rotation when fired - if the ball does in fact distort to this semi-cylindrical shape, such rotation would not be possible. Thus "hook" shots caused by a yawing spin couldn't happen.

Bill,
If you do the test as I described for yourself, you will see that the tracks or skid marks on the ball are to consistent to be made by a ball that is merely bouncing through the barrel as a result of yaw and pitch. If the ball did not seal to the bore and be held relatively straight, air blowing past the ball on one side would generate a great deal of spin as the other side would be slowed down by its contact with the bore. The same prinicple that generates the spin on the ball that goes through the curved and very large bore barrel of the Tippmann flatline barrel. The curve of the barrel forces the ball against the wall of the tube, creating friction while propulsion air can blow past the ball on the other side to amplify the spin. The biggest drawbact that I see in spinning a paintball is the fact that they are not round and feeding does not allow for the ball to be fed into the chamber with the seem of the ball in the same orientation to the axis of the barrel with each shot. By breach loading a paintgun to place each ball in the chamber with its seem in a controlled orientation to the barrel it is fairly easy to see how the flight of the ball is affected by the orientation of the seem when it is fired. When the seem of the ball is against the full perimeter of the bore; muzzle velocity is just a bit higher and the hits on target will be pretty much in the same group but with a somewhat vertical spread. When the ball is loaded so the seem is placed lineal to the axis of the bore, (starting with a 12 oclock and 6 oclock orientation) the center of the shot group will be in a different location on the target and show a more horizontal spread. Loading with the seem orientation changed on either axis creates shot groups in a clock-like pattern on target. Also noted in these same tests was that the less spin seen on the ball in flight, the tighter the shot groups; regardless of the orientation of the seem. Velocity and muzzle blast also plays a big role in the size of the shot groups.
It is important to note here that the first of the above tests was done with a known gun with an 11" barrel and precisely tuned valving but ran the same tests with a test bed unit in order to see the results of varying barrel and valve configurations.



Originally posted by billmi


I've had a look at some of the high speed video and stills Tom has taken of balls fired through a clear barrel (some is included in the Automag RT video.) If the balls are distorting, it is too insignificant to see in the photographs. An important question to which I hope Tom can supply an answer is, where those done with gelatin paintballs, or with Perfect Circle paintballs, which have a more rigid plastic shell?


I'm not saying that the ball flattens out like a pancake; it simply can't do that within the confines of the barrel. However, it dosn't take much "distortion" to make a big difference in how the ball acts when it is fired. Just as it takes only one small speck of paint, in an otherwise pristine barrel, to send a ball off into never-never land when shot.
What I am saying, is that we need the ball to upset somewhat so that it can seal against the bore and achieve maximum potential from the internal balistics. However, we also need for the internal balistics to cease acting on the ball before it leaves the barrel if we are to expect any kind of consistency from a relatively innconsistent projectile.
Also, (in keeping with the thread) closed bolt firing seems to give me the best opportunity to to dial in my equipment and make the most out of every ball shot.


Originally posted by billmi


Please also note, I will happily disagree with Glenn on theory or interpretation of the results of a test or experiment, but this in no way means I don't respect his viewpoint. There are a lot of people in the industry that will support a certain theory regardless of its validity, simply as a means to market their product. Basically they have a product, and whip up a theory to explain to you why it's the best in the world and you need to buy it. Glenn on the other hand, has used his theories of paintgun operation to build quality products, and is one of the few manufacturers/customizers to understand the concepts of old world craftsmanship.

See you on the field,
-Bill Mills

Thanks for your support Bill. I am about as old school and old fashioned as they come. I just can't operate on theory or conjecture besides having a starting point in the search for actual improvement. The bulk of what I know about paintball equipment and shooting paintballs has come from a great deal of trial and error and/or trial and success that has been focused only on how to get my own equipment to allow me to play my best game. When common sense thinking leads to a success a process will become a standard part of what we do and I will gladly share the results with others. I have also learned a great deal from my errors as well. :rolleyes:
Sometimes it gets difficult to share something without it looking like a marketing ploy and many just do not understand that, that just is not my style. You know my views on common marketing practices because we have discussed it on a personal basis.

Paladin
11-16-2002, 04:41 PM
Originally posted by billmi


Glenn,

In a previous post you said the open/closed bolt accuracy test did not show a difference between bolt position because the test gun was not tuned for optimal closed bolt performance.

Would it not be a possibility that it's the tuning that is optimizing efficiency and consistency in the gun setup, rather than bolt position that has provided the improved performance in your experiences?

Se you on the field,
-Bill Mills

Yes indeed, the tuning makes a huge difference. As I see it, closed bolt operation gives me a better opportunity to tune the shot effectively. I must reiterate here that my stand on closed bolt operation is based on a comparison with a open-bolt firing system that uses the same blast of air to both launch the projectile and cycle the action reward in preparation for the next shot. ie: a blow-back operated system like the Stingray and numerous others . (in my opinion, the valving for a Stingray leaves much to be desired regardless of how it is to be used. I've just not been able to get real good results from the Crossman style inline valve used in the Stingray)
Although, awhile back I had the opportunity to convert a Spyder from blow-back operation to closed bolt firing with our pneumatic automation system and the improvement to overall performance was quite noticeable even with the only change to the valve being a valve stem that did not allow flow to the rear for blow-back cocking. Better efficiency, better consistency and a much tighter shot grouping were immediately evident. The improvement in performance may have only been the result of seperating the feeding action from the firing action. This allows the hammer to strike the valve more consistently because it doesn't have to overcome variables in ball size and positioning when feeding and it doesn't have to deal with the drag related to the o-ring on the front of the hammer. I also believe that giving the propulsion gas a solid wall to push against instead of having an amount of the same blast of air drawn off to the rear to blow the action back, aids considerably in achieving optimum effectiveness from the shot.

If my typing wasn't so damned slow, this would be a great deal easier.:)

AGD
11-16-2002, 11:55 PM
Originally posted by pbjosh
AGD-

That is a given. The balls spin when they leave the gun. All of them do.
Spin is the entire issue for accuracy and range.


Josh, this is a very broad statement. Yes the Magnus effect is real but you have not proved that a paintball spins with every shot and that this has an all encompasing effect on accuracy. I could say with just as much confidence that the ball never spins, and all the inaccuracy is due to wind currents throughout the balls flight path which buffet it off course.

Glen,

It's dangerous to look at the ball scuff marks and deduce what's happening in the barrel. A much better approach is to lightly powder the barrel, shoot one shot and inspect the bore.

AGD

Blazestorm
11-17-2002, 12:02 AM
Why does Tom get to be the smart one... I wish I was smart :(

Paladin
11-17-2002, 12:50 AM
Originally posted by AGD


Glen,

It's dangerous to look at the ball scuff marks and deduce what's happening in the barrel. A much better approach is to lightly powder the barrel, shoot one shot and inspect the bore.

AGD
Not so dangerous if you wait until the ball ends it flight before inspecting it closely.:D

Since I know there is generally more than one way to "skin a cat", I'll give the powder method another try or ten when I get to the shop on Monday and see what that tells me.
However, I don't have a good bore scope that would allow me as close a look as I would like.

pbjosh
11-17-2002, 07:55 AM
AGD-

I have been around for a little while, and I know only being here in the sport for 12 years next spring makes me seem like a lightweight compared to Yourself, Glenn and Bill.

But it would be hard for me to look back at a couple solid years of play and remember a time, while shooting two tone paint, that I DIDN'T see it spin.

Prove to me that my Eye's are wrong, and that the ball is NOT spinning, ever.

As for blaming the wind, I have shot paint out a moving vehicle. Quite often in the past. And in heavy wind. And we have had some serious wind in Alaska.

If what your saying, that the ball doesn't spin, that it is only wind affects- I am sorry, I would need THAT to be proven. These are balls, they are moving through the air at 200mph. Inherent spin would affect them more then light random air currents. A gun that shoots lousy will still shot lousy on a perfectly calm day. The gun is causing something to go wrong. It is causing spin. Another gun, accurate as hell, will still shoot straight on a slightly windy day. Because two guns shoot differently in the same wind conditions. That alone would make the "and all the inaccuracy is due to wind currents throughout the balls flight path which buffet it off course. " statement incorrect. The problem is something that happens before the ball can even hit the "wind currents". If that was true, barrels would have NO affect on paint, different guns would all shoot the same on a given day.

Since what you are saying is that the gun doesn't affect the accuracy at all, all the gun, barrels, shoot exactly the same on any given day- Because of wind currents-

I can prove that wrong.

Josh

flanders
11-17-2002, 09:12 PM
ok well i just did a huge *** project for cience testing just this, open vs closed bot, i used my tricked micro cocker and a buddy's dark angel

what i found was that over all at the range i did (25 yards) both guns are pretty dman accurate, although over all my cocker was slightly better not by much if u want more detail im me

ezrunner
11-17-2002, 10:13 PM
can you post results, including:

paint used,
barrel(s) used
and any wind or temp info you
had?

-rob

kilaueakid
11-17-2002, 11:33 PM
Is it possible that the ball starts to spin as it is being pushed past the detent/s from friction, and when the air blast hits it, it increases the speed of the spin. As each ball size differs, this friction could differ or not exist, thus making a ball occasionally move left to right, or up/ down depending on what type of friction. There could also be some type of rolling action happening while the ball is dropping into the breach??

kila

AGD
11-18-2002, 03:37 AM
Josh,

I am not saying that the wind currents affect the ball. I am using that as an analogy to compare it to what you are saying.

Against my better judgement I am going to post some of my actual testing data here in the forum. I want to see if you all take the time to really analize it and come to some conclusions. I am afraid in doing this that everyone will just use the info to argue their own side instead of really trying to understand what's happening.

Maybe its the right time now that we have a bunch of "on the ball" people here in this forum. I am going to close this thread in order to start another one thats more on target with the discussion at hand. Lets move over there. I will put the data up in the data thread and then you can copy it down to the new thread for discussion.


AGD