Could the cocker shoot farther?!

[Magluvr]

Ok....

I know that many of you have heard this debate many times about cockers shooting farther blah, blah, blah...

But, I was just thinking about it and something popped into my head. Is it possible that a closed bolt system would have a flatter trajectory than an open bolt system?

In both these virtual simulations the marker is being shot very slowly (aka 1bps). It does matter.

The reason being that in firing a closed bolt system, the ball is completely at rest (not moving at all).

The open bolt system, when it pushes the ball forward into firing position is causing the ball to roll forward. Since the ball when shot is actually rolling, it would be the opposite of the flatline effect (b/c the ball is "rolling" the opposite direction.)

So essentially if the bore was loose enough on the ball, it wouldn't stop the roll, and actually cause the ball's trajectory down range to drop more than it should.

Hence, the cocker would have flatter trajectory and longer range!

This if true would prove a couple things:
1) Why markers like the cocker seem to have a lower rate of fire before "visible" (not speed related) shoot down. Because as the cocker shoots faster it acts more and more like an open bolt and therefore less range, even though the chronograph may show that it is shooting the same exact speed.
2) Closed bolt markers then could actually shoot farther.

P.S. Look at the galactic zbody, it only spun the ball for a very little while and it could produce the flatline effect. So, I don't think that it is too small a "spin distance" for it to have any effect, sort of argument would be valid.

[FooTemps]

cockers dont' shoot further... period...

300fps = 300fps = 300fps = 300fps

That means that if the ball travelled for 1 second and then stopped suddenly, it would have travelled 300 feet...

300 feet per second

edit: AHHH! heh, sorry bout not reading into it enough, knee jerk reaction type response.
It still doesn't matter, the ball is moved so fast it doesn't really roll...

[Magluvr]

READ BEYOND THE TITLE!!!!!

Please, for future posters read the little argument before commenting.

The flatline will shoot farther and the balls coming out the end of the barrel are going at 300fps!

So the answer is:

"No, 300fps != 300fps necessarily in distance terms." (!= meaning does NOT equal.)

And no this isn't an argument solely for the possibility of longer range on a cocker. I used the cocker as an example since it is the most widely known and identified with of any closed bolt marker out there.

[ScatterPlot]

I see where you're coming from. However, I don't know if the ball would necessarily roll too much. There's not very much friction and I think inertia would keep it from spinning without something with high friction.


PS-Man I hate it when people respond according to title alone!!!!

[spantol]

This claim seems to be the key to the whole thing, and I'm not buying it:


Originally posted by Magluvr
The open bolt system, when it pushes the ball forward into firing position is causing the ball to roll forward. Since the ball when shot is actually rolling, it would be the opposite of the flatline effect (b/c the ball is "rolling" the opposite direction.)

I've just done some quick-and-dirty "experimenting" with a mag bolt, some paintballs, and a barrel, and it doesn't appear to me that the ball does much, if any, rolling while the bolt is pushing it. If there's no rolling occuring, the argument falls apart.

[Magluvr]

spantol-

Did you try with just the ball in the breach?
How about with a stack of balls on top?

Just curious if there is any difference, I haven't had time outside of schoolwork to test the idea.

[Joni]

Well, we have seen TK's pictures of a ball being fired. I guess they are being shot from an automag, and you can clearly see that there is NO spin on the ball. The whole argument dies with that...

[trains are bad]

It was cool theory though, props. BTW I go "=/="

[Glickman]

ok well yes hes right about the fps thing, but most people buy a cocker for its flatter trajectory. while i dont know exactly why it does have one, it does, maybe because they have more time to recharge (u know like in milliseconds) than other guns, i actually find tho, that in the SAME CONDITIONS with a fps difference of only 5 fps, my TRIX shoots with a flatter trajectory...

[spantol]

Let's see your data...



Originally posted by Glickman
ok well yes hes right about the fps thing, but most people buy a cocker for its flatter trajectory. while i dont know exactly why it does have one, it does, maybe because they have more time to recharge (u know like in milliseconds) than other guns, i actually find tho, that in the SAME CONDITIONS with a fps difference of only 5 fps, my TRIX shoots with a flatter trajectory...

[SlartyBartFast]

What on Earth is a "flater trajectory"?

Unless you're using a z-body mag or a flatline barrel, all guns shoot the same distance.

Most of the "flater trajectory" stuf is more due to the height of the guns.

Mags have low bodies so you sight down the barrel and the barrel is naturally held more horizontal to the ground.

Cockers and others have tall bodies and if the body and barrel are used to sight the barrel is held with an upward tilt.

Put the barrels on a horizontal surface to fire and ALL markers will shoot the same distance.

Except for the z-body or flatline barrel which will make the ball travel farther but gain you little to none in terms of USEFUL range. You can just annoy people more by hitting them with more bouncers.

[SlartyBartFast]

On another note, any and all wobble roll, or other movement of the ball before the shot is negated by the
64000 ft/s^2 acceleration of the paintball down the barrel.:eek:
Thats 1984 g's.:eek:

On another note once it leaves the barrel accuracy can't be improved because anything done by bolt or barrel is negated by vortex shedding and the inherrent randomness of paintball flight.

[Magluvr]

Slarty-
Could you explain this thing about the taller guns, would seem to have a flatter trajectory. I don't understand how a taller bodied gun could appear to have a flatter trajectory, merely because their taller.

I'm confused :confused:

Joni-

Could you please post a link of the pix, because I haven't seen that one?

Trains-

It kinda a habit, I did a little bit of computer programming (C++) a while back and haven't been able to break the habit yet.

[danheneise]

i still don't see what's so different with open/closed bolt, in each system, the bolt is fully forward and the ball is AT REST before air is shot out, the only way a ball is going to start rolling farther forward is if you have to big of a barrel, trust me, take your 'mag barrel, stick a paintball in the top hole, and with your finger, or better yet, with your mag's bolt push the ball in as if it is loading, now load it in only half way, as long as you have the right paint to barrel match that ball should be pretty snug in the barrel half way loaded in, if it's rolling then trust me you need a smaller bore barrel, as long as i'm shooting a proper barrel to paint match gun, i have rarely noticed any spin at all which would indicate very little or no rolling of the ball in the barrel after it is already loaded in

Dan Heneise

[spantol]

I believe this is the pic in question:

http://www.automags.org/forums/attachment.php?s=&postid=526782

[Magluvr]

Does anyone know what type of barrel setup that was?

PF or SF (if so H/L or H/R) or CF

I noticed that the ball was rotating slightly off-canter to the sides. (I think this is what caused the ball to drift off the centerline.) Indicating that the detent was on the on the left hand side of the marker. Meanwhile, there appears to be no "up and down" spin. Interesting!!!!

So, the detent -since I have no other idea of what would cause the ball to spin that way-...
Do you think that the induced spin is consistent? If so then there should be no accuracy problems because ALL the balls would travel along the same path.
If it isn't consistent, then is there any conceivable way to remove the induced spin, (except for removing the detent)?


P.S. I was thinking about it and am guessing that the marker is centerfeed with the detent on the left side of the marker.

[Cristobal]

Magluvur: The ball is moving in flight not because its spinning on account of a detent or other frictional force it encountered in the breech/barrel. Rather its moving like a knuckleball because paintballs are simply bad projectiles. The phenomena is called vortex shedding, and it is discussed in detail in one of the spin physics threads.

The z-body needs a very loose barrel if it is to work well, if at all. Any ordinary barrel induces too much friction and effectively negates any spin the ball picks up in the breach. (See Tom's tech tips.) I find it highly doubtful that a detent could impart enough spin on a paintball to cause a noticable effect on its flight -- especially one which would excceed the random motion caused by vortex shedding.

[Magluvr]

Cristobal-

Correct me if I'm wrong, but... From my understanding vortex shedding would cause the ball to drift, or jerk in any direction. I don't think that it would cause the object to spin. And that the paintball is spinning on a vertical axis is clearly seen in the pictures.

.....Hold the phone!!!!!......

Um, I was checking the pictures again and was wondering are the balls in the picture the same ball, or are they each their own discrete ball?

If they are discrete than everything I have said in this post and previous is cannot be validated by the photo. So, before I bother continuing could anyone clarify the picture.

P.S. If the picture is of discrete balls then is there any place I can find a picture of the same ball in flight. Because, discrete balls won't show spin of any kind.

[Cristobal]

Originally posted by Magluvr
Cristobal-

Correct me if I'm wrong, but... From my understanding vortex shedding would cause the ball to drift, or jerk in any direction. I don't think that it would cause the object to spin. And that the paintball is spinning on a vertical axis is clearly seen in the pictures.



Yes, my understanding is that they are all the same ball -- as I recall, Tom said they used a timed strobe to illuminate them in flight.

I don't know whether vortex shedding would induce spin on paintballs not. As best I undertand paintball fight, my contention is that the slight lateral motion of the ball in the bottom picture is more likely due to vortex shedding than any spin it had coming out of the barrel.

[SlartyBartFast]

Originally posted by Magluvr
Slarty-
Could you explain this thing about the taller guns, would seem to have a flatter trajectory. I don't understand how a taller bodied gun could appear to have a flatter trajectory, merely because their taller.

If the top of the body is higher than the top of the barrel, people tend to sight down the top of the body to the end of the barrel. The barrel is then obviously tilted upwards (but not necessarily obvious to the shooter). When shot the ball goes further. Not because of elves or any inherrent majic in the marker but because the gun was tilted ever so slightly.

Sighting along the top or side of a marker like the Mag, the gun tends to be much more horizontal.

[Miscue]

Not Deep Blue material, moving.

[nerobro]

The Z body produces a LOT of backspin. (comparable to the flatline) And a lot of broken balls if you're using it "properly" (that's with the pad down) Most z bodies are used with the backspin element deactivated. (due to ball breakage, and lack of avilablity of large enough bore barrels...)

However, you're right. sometimes, when there's the last ball in the gun, with a non foamie bolt, you MIGHT get some topspin. However, not enough to matter. IIRC, under 6000 rpm ball spin doesn't really matter. Over 6000 rpm is where you see it's effects.

[FallNAngel]

Originally posted by danheneise
in each system, the bolt is fully forward and the ball is AT REST before air is shot out

Technically, they're not. In a closed bolt system, the ball is loaded and then air is released. In an open bolt system, since the bolt and hammer are linked, when the hammer is moving to open the valve, so is the bolt..which means the ball is moving too. The ball may be moving only a fraction of an inch, but it's still moving. On the other hand, it's not rolling enough (if at all) to make a difference, which is why I said technically. ;)

[DirectHitSniper]

well in REAL guns it has been proven that closed bolt IS more accurate. which is why snipers use them etc.

could someone explain that to me?

[FallNAngel]

I'm not quite sure on real guns and why snipers would only use closed bolt... but in either case, paintball isn't real guns. You're trying to get the same accuracy with a small paint filled gelatin ball that you can with a solid pointed piece of metal... it's just not going to happen.

*edit*
I just thought that I may have said this in a harsh awy. I'm not trying to be rude or anything, it's just that paintball isn't the same as real guns. What works in one, won't always work in the other. For the purposes in paintball, just open vs closed bolt doesn't have enough of an effect on the ball to make a difference.

[DirectHitSniper]

hehe I didn't take it as rude :p

even if the paintball is round and filled with gelatine... its still shot out similar to a real gun.

maye if anyone knew why closed bolt on real guns is more accurate it could make this easier to understand..

[nerobro]

They aren't filled with geletin. They are filled with ethelyne glycol or other non water liquids. The shells are geletin.

And paintballs DO behave as bullets do. Round bullets. Notice that bullets are not round ;-)

Bullets have a LOT more energy behind them. And the forces seen are much higher. think 10,000psi versus 120psi. Guns deform. Paintball guns, do not.

[cockermongol]

I notice a difference in ark between my new BKO and my old cocker. I used cockers for 2 years and then when I just got my BKO I noticed a difference in the way it shoots (yes, chronoed at the same velocity).

[FallNAngel]

Originally posted by DirectHitSniper
even if the paintball is round and filled with gelatine... its still shot out similar to a real gun.

The way that they're shot is *kinda* similiar.. They both get pushed out of a hollow tube..that's about it. The barrels on real guns can have rifling, which does nothing for paintballs. The shape of a paintball (spherical) allows for vortex shedding which the pointed/conical shape of a bullet does not, which can damage the paintballs accuracy. Spin can be put on a bullet, where there is none on a paintball.

[Mindflux]

Originally posted by cockermongol
I notice a difference in ark between my new BKO and my old cocker. I used cockers for 2 years and then when I just got my BKO I noticed a difference in the way it shoots (yes, chronoed at the same velocity).

That's ALL in your head.

[cockermongol]

Originally posted by Mindflux

That's ALL in your head.
Don't give me that BS. I know the difference.

[Jack & Coke]

Could the cocker shoot farther?!

Yes... and flatter too!

Why?

Because you can cheat with a two-stage trigger system (auto-cocking).

All auto-cocking style guns can be set up so you can chrono at one speed (say 300 fps), and then shoot an "in game" hot-shot at 300+ fps.

That is why the shots "appear" to go flatter or shoot farther. It's because the fps is higher. Not because of any rolling spin of closed bolt magic.

The normal opperation of the auto-cocker system goes something like:

1. sear release
2. hammer hits valve
3. air propels ball
4. back block recocks hammer

However, if you setup your timing so that the gun recocks right at the moment the hammer hits the valve, you can make it so that the bolt starts to recock a split second before the valve closes after being struck by the hammer. This will give you a little blow back up the feed tube and give you a lower fps (not to mention less efficiency). This usually happens on a very very quick pull. So what you do next is dial up the main spring so the gun shoots faster and say on look... 300fps!

Now during the game, if you pull the trigger slower, you may get it where the bolt recocks after the full amount of air is expelled from the valve. Thus ALL of the air goes to shooting the ball (i.e. no blow back). This will give you more velocity. 300+fps :)

The trigger cadence, rythm, and speed will sometimes influence the velocity by affecting how much air goes to the ball. It all depends on your gun's automation timing.

You can set up the timing where there's really no difference on how you pull the trigger. Or you can set it up so that it shoots a little hotter by trigger control.

Sometimes this happens by sincere accident and people start saying, oh wow! Auto-cockers do shoot further and flatter!:eek:

Well duh... it's because you're shooting a little bit hotter than everyone else.

[Jt$uper$tar]

I own both a open bolt and a cocker. I find at 280 that the closed bolt is far more accurate even with the stock barrel, it also seems to have a flatter trajectory

[Jt$uper$tar]

lol but to be realistic i really think this is coming down to a cocker VS mag

[Mindflux]

Originally posted by cockermongol

Don't give me that BS. I know the difference.

:rolleyes:

At BEST one has less kick than the other, causing you not to angle the barrel up slightly when you fire it giving it a arc like appearance.

QUit being a dillwad.

[Jt$uper$tar]

lol i get like no kick, its only on the older cockers where a lot of kick is a problem

[Jack & Coke]

http://www.automags.org/forums/attachment.php?s=&postid=512608

[Lohman446]

Interesting, the theory stands sound as theory... though I do not think it will test out as such.

Let me give an example, I have an early run ULE body and had a sticky detent - since fixed by spacing and a Kila magnetic detent. I was also shooting like a .690 CP barrel. My shots would curve, to the right in the air - not with a great consistency cause of the detent sticking sometimes worse than others.

SO yeh, a ball rolling downward could cause this, but I think if it was it would be soo pronounced as to be obvious.

I love the points made so far, but do note, if cockers (or any closed bolt or any style marker) did shoot farther, I think it would already have been scientifically and undebatably proven - and SP would have patented it.

[Jt$uper$tar]

but technicaly because of that spin wouldn't the cocker be more accurate, assuming that the mag adds a touch of spin to the ball

[cockermongol]

Originally posted by Mindflux


:rolleyes:

At BEST one has less kick than the other, causing you not to angle the barrel up slightly when you fire it giving it a arc like appearance.

QUit being a dillwad.
Actually, the BKO has less kick.

But the cocker still shoots farther. I know this from using both guns.

[FallNAngel]

Originally posted by Jack & Coke
However, if you setup your timing so that the gun recocks right at the moment the hammer hits the valve, you can make it so that the bolt starts to recock a split second before the valve closes after being struck by the hammer. This will give you a little blow back up the feed tube and give you a lower fps (not to mention less efficiency). This usually happens on a very very quick pull. So what you do next is dial up the main spring so the gun shoots faster and say on look... 300fps!

Now during the game, if you pull the trigger slower, you may get it where the bolt recocks after the full amount of air is expelled from the valve. Thus ALL of the air goes to shooting the ball (i.e. no blow back). This will give you more velocity. 300+fps :)

That's really outlandish. That's like saying "it'll shoot farther if you thumb the rod!" ... I think we're all trying to look at things under "normal use" situations. In either case, once you crank up the velocity to 300, then pull the trigger slower to get the spike of say... 320fps+, then you have issues of the ball curving from going to fast... not exactly a flatter shot anymore.


Originally posted by Jack & Coke
The trigger cadence, rythm, and speed will sometimes influence the velocity by affecting how much air goes to the ball. It all depends on your gun's automation timing.

With the marker properly setup, it actually won't make much of a difference at all. Evidence of this is with EBlades / Race frames. You can time how things work down to the millisecond. Being able to open the bolt 3ms after the sear is released is going to be a lot more accurate (and faster)than your finger is. Time it right and you won't have problems. Can it make a difference? Yeah.. Do I think that anyone would believe that's where the myth originated? No.


Originally posted by Jt$uper$tar
but technicaly because of that spin wouldn't the cocker be more accurate, assuming that the mag adds a touch of spin to the ball

Yes, but if there's only a touch, there won't be enough to make a difference ;)


Originally posted by cockermongol

Actually, the BKO has less kick.

But the cocker still shoots farther. I know this from using both guns.

So.. when was it that you viced each and actually did an experiment with the two? Just playing with each and saying "The cocker shot farther" isn't really scientific.

[Jack & Coke]

Originally posted by Y-Grip


even if this were true, it's bullpucky for me cuz Warp Feeds eliminate all blowback effects on the paintball. I also use a powerfeed.



you obviously don't understand what is happening...:rolleyes:

[bryceeden]

I have both a mag and a cocker, and just to see I set both up in vices, and tested at the exact same velocity(took over an hour to get it right) I used the same barrel, and the same paint. They went the same distance, and when tested for accuracy they had near identical groupings. The difference is in the user, the mag has a forward kick that ever so slightly lowers the barrel while the cocker has a backward kick that slightly raises it, that is why people percieve different results on the field, but these differences are very minimal unless you hold you gun VERY VERY loosly, at which point you have no accuracy. So literally no, the cocker doesn't shoot farther, but in the feild it has about 2-10 feet on the mag. I think the siting down the barrel theory makes alot of sence as well. I do prefer the mag over the cocker in the end.

[Brophog]

Open your mouth and let all the ignorance out, shall you.

Jack and Coke is talking about chrono cheating with a cocker......

[Jack & Coke]

Brophog is correct.

Y-Grip, chill out and try not to get so worked up. There's no need for internet chest puffing and flame-baiting keyboard warrior posts. Welcome to AO and try to remember, this is not PBN. :)

[Jack & Coke]

Well at least you're making up for lost time... (21 posts so far in one day) ;)

[CaliMagFan]

lol you guys are looking for the reason that real guns use closed bolts to be more accrate thru the eyes of paintballers... and by the way... they dont use them to be more accurate... lol... the closed bolt design is to save energy.... if i'm firing a bullet, 1 bullet, with one chance to hit 1 target, i dont want to waste the energy that i have stored in the bullet's charge in the cartride out a breech... the reason: snipers shoot far, that is a given... they want to be able to get they bullet out there with every bit of the energy from their gunpowder as possible... semi auto rifles and handguns use the gas from previous shots to recock themselves in most cases... snipers dont need to put 10 bullets on a target, thats not the point...

so... the closed breech doesnt make a bullet fly any straighter-- lol--- it just makes sure there is no "blowback" or other means of lost energy, such as gas cocking mechanisms....

fyi blowback is governed by many atmospheric variables... so increasing the powder charge and making them open bolt would be ok.... the only problem is you dont know how much energy you will lose at a given shot.... so its just less consistent as far as muzzle velocity goes on guns...

you guys... so caught up in physics, missing the simple stuff sometimes...

the word of physics is based on common sense btw.....
-kyro

[Brophog]

The other reason that snipers use the closed bolt, bolt action is for silence.

It allows them to very quietly, and on their own terms remove a spent cartridge and load a new one. With a semi auto, it would re-chamber this cartridge automatically, which could give away the snipers position by either sound and/or visibility.

The real reason this argument is bunk is that almost none of you will actually take a single shot. Perhaps, in a single shot status, the closed bolt would be more stable, but how often are any of you going to shoot either an open bolt or closed bolt for one shot. Once you start shooting fast, both systems will behave very much the same.

Now, for me, I rely on single shots for a good portion of my eliminations. Do I feel that the closed bolt design is gaining me anything? I can't say I do. Its become one of those things to argue, just for the sake of argument.

[AGD]

HA! I even thought that closed bolt real guns were more accurate. Thanks Calimag your post made perfect sense!

The paintball has random spin orientation coming out of the barrel. The spin also varies between 0-3000 rpm.

You can make yourself feel better by thinking anything you want about how this gun is better than that gun but that doesn't change the facts.

AGD

[Doc Nickel]

Um, Tom? Haven't you ever spent time around any real firearms? CaliMagFan's explanation is (no offense Cal) complete nonsense.

The difference between closed and open bolt firearms has absolutely nothing to do with conserving muzzle energy; simply put, there's a hefty surplus of energy available when firing a cartridge- that is, after all, where the ear-splitting noise comes from: surplus energy not being used to drive the bullet.

Firearms use an open-bolt arrangement almost exclusively as a simplified full-auto mechanism.

In a closed-bolt full-auto, the bolt cycles, chambering a round, and once closed, a seperate hammer is released, striking a seperate firing pin to ignite the cartridge.

In an open-bolt, as the bolt closes, a fixed firing pin in the breechface ignites the cartridge. The bolt takes the place of the seperate hammer and firing pin. All the trigger mechanism has to have is a simple sear-catch not substantially different than that in any Spyder or old Tippmann SMG.

And as far as accuracy goes, what difference there is, is simply because the open-bolt is manufactured to "looser" tolerances (open bolt being used primarily in cheap/low-cost pistol-caliber submachine guns) and it has a typically huge (since the gun is a blowback) bolt slamming forward, which causes the shot to point low.

Again, none of that has anything to do with conservation of cartridge energy. There is far more energy available in the propellant than the bullet can use: much of it is directed back to the shooter as recoil, a great deal goes to make a bloody great lot of noise, and a nontrivial portion goes to heating up the barrel and the bullet itself.

Almost no firearm, save for perhaps the .22 short, allows all of its powder to burn before the bullet leaves the barrel- which is why, as far as firearms are concerned, a longer barrel provides greater velocity.

In short, there is far more than enough energy available to tap off a small portion to operate either a blowback or gas-operated semiautomatic mechanism.

There is essentially no analogue between open and closed bolt firearms, and open and closed bolt paintball guns, with the possible exception of the recoiling mass as it cycles. (IE, a bolt flying forward tends to drop the muzzle.)

And Brophog, "silence"? The noise of the loudest action in the world being cycled is nothing compared to it being fired.

You may have in mind the fact that some suppressed pistols are often fitted with a slide-locking mechanism, so the sound of the action cycling isn't a giveaway, but that sort of thing is intended for close-range work.

The reason "snipers" use a "closed bolt" is, well, because basically any weapon of a high enough quality (as in, anything not cheap stamped sheetmetal) to be used as a "sniper" rifle, and of a large enough caliber (any non-pistol caliber) to be effective at longer ranges, will basically by definition be a closed-bolt.

In other words, since there are so few "open bolt" rifle-caliber rifles as to approach zero, it stands to reason that "snipers" would use a closed-bolt.

The only open-bolt rifle-caliber arms I'm aware of are the M2 .50 cal and the old Browning BAR of WW2; both of which, while they have been pressed into occasional "sniper" type roles, are not by any means well-suited for the application.

Doc.

[Doc Nickel]

Originally posted by Y-Grip
Finally someone who knows what they are talking about. Also about the recoil/kick thing, it has been reduced because of LEVEL 10. The Superbolt II is the lightest bolt in paintball as of today.

Well, lightest 'Mag bolt, maybe. The 1-1/4" long, mostly-hollow aluminum bolt out of a PT Extreme is (at a guess) less than half the weight of an LX bolt.

If you want to count reciprocating mass, that's a different story, as the same PT would then have the hammer involved.

But even still, the all-Delrin, almost entirely hollow bolt out of, say, an '03 Shocker, is considerably lighter than the L-10 bolt.

Doc.

[bryceeden]

Originally posted by Y-Grip
Finally someone who knows what they are talking about. Also about the recoil/kick thing, it has been reduced because of LEVEL 10. The Superbolt II is the lightest bolt in paintball as of today.

And if you watch a newb with a mag that just had the LX put in they will very commonly say that the marker shoots farther, thats what got me interested in doing the tests on accuracy and range as a result of recoil.

[billmi]

Originally posted by CaliMagFan

so... the closed breech doesnt make a bullet fly any straighter-- lol--- it just makes sure there is no "blowback" or other means of lost energy, such as gas cocking mechanisms....


I don't quite understand what you meant by that.

Gas cocking mechanisms are used on closed bolt firearms. Gas from midway down the barrel is routed to the recocking piston that unlocks and opens the breech to chamber the next round.

See you on the field,
-Bill Mills

[AGD]

Doc,

Actually I a real firearm illiterate. I grew up hunting with everything BUT firearms (seemed to easy). Thanks for the info!

AGD

[Crighton]

Originally posted by Doc Nickel
The only open-bolt rifle-caliber arms I'm aware of are the M2 .50 cal and the old Browning BAR of WW2; both of which, while they have been pressed into occasional "sniper" type roles, are not by any means well-suited for the application.

Doc.

The original version of the Sturmgewehr 44 was the MkB-42 which fired from an open bolt. Of topic and all but an interesting factoid.

[BlackVCG]

One of the primary reasons that heavy machine guns like the M2, M60, M249, etc. operate from an open bolt position is to keep the next round from "cooking off" under heavy use, the barrel will get hot enough that if the cartridge is chambered, the heat in the barrel wall can preignite the powder and "cook off" the cartridge. Open bolt doesn't have a catridge waiting in the chamber so the cartridge is never in the barrel until it's being chambered to fire and then extract.

Closed bolt is used in sniper rifles and basic rifles simply because open bolt in a gun of that type would be utterly pointless.

[CaliMagFan]

edit: doc, i do take offfense to you calling what i said nonsenical... thanks btw

hey, that was the point of the firearms talk... i only use my knowledge of firearms use and some teardown... i think that DOC has a better grasp of the whole thing than i, as far as the facts. but doc, in the real world, when you're waiting to hit your target for at least a second after firing, dont tell me that gas escaping an open breach would have helped you hit it easier... i shoot these rifles, i know what 800+ yards to the target is like, an its the quest over control of variables that puts the closed bolt system into play in precision rifle shooting...

i think i'm in as far as i want to be in this quasi-paintball topic..

i think i'm going to design a sabot-shaped paintball and loading system tonight.--- wish me luck producing those projectiles... lol

-kyro

[Doc Nickel]

but doc, in the real world, when you're waiting to hit your target for at least a second after firing, dont tell me that gas escaping an open breach would have helped you hit it easier

You're right, gas escaping an open breech doesn't help you hit the target "easier".

But it doesn't make it "harder" either. And, like paintball guns, what the gun does after the projectile has left the barrel has absolutely no effect on where or how far the projectile goes. Once the bullet has left the barrel, the gun can shake, rattle, roll, cycle, slam or wobble all it wants and it can't affect the bullet even if it is flying for a full second.

In your first post, the one I was replying to, you said:


[T]he closed bolt design is to save energy[.]

And that's not the case, at least in the way you're implying.

The bolt is closed because that's the whole purpose of the bolt- to close the breech and seal it to prevent the loss of propellant gasses.

It doesn't matter where it starts from, open or closed, ALL firearms fire from a closed, sealed breech. (Just as ALL paintball guns fire with the bolt closed or breech sealed.)

You follow that with:


if i'm firing a bullet, 1 bullet, with one chance to hit 1 target, i dont want to waste the energy that i have stored in the bullet's charge in the cartride out a breech

Again, there's far more energy in a cartridge than the bullet uses; I believe less than half of the propellants' potential energy actually goes to drive the bullet. Some powder will actually leave the barrel unburned. (When the M-16 was first issued, the Army changed the propellant spec- the new ammo gave a higher velocity, but fouled the guns' gas system and bolt head with unburned powder granules.)

What you're looking for is not raw power (IE, extracting every last bit of energy to create the most projectile velocity) rather, you're looking for maximum consistency- IE, putting the bullet in the same spot, at the same velocity, every time. What we call "accuracy".

"Power" is irrelevant. As far as target shooting is concerned, most rifles will impart enough velocity to the bullet so that it will still penetrate a paper target even at 800 or a thousand yards. Power is meaningless- accuracy is the important part.

Even for "wet work" (a "sniper" shooting a person or a hunter shooting an animal) most medium and larger caliber rifles will still hold more than enough energy even at extended ranges to be lethal.

With the surplus of energy used to fire the projectile (again, all that noise, smoke and barrel-heating, is basically waste or surplus energy) the tiny bit tapped off to operate a semiautomatic mechanism (whether it's recoil-operated or gas-operated) is statistically insignificant.

In fact, you can check it yourself. Borrow an M1 Garand or M1-A, and chronograph the same load both normally (semiauto) and with the gas system shut off (both rifles have a provision for doing so.)

You may very well see a slight increase in velocity, but again, the key here is not the velocity itself, it's the consistency of that velocity. As long as the action uses the same amount of energy for each shot, your consistency remains the same, and thus maintaining your accuracy.

Continuing:


an its the quest over control of variables that puts the closed bolt system into play in precision rifle shooting[.]

And my point is that you're talking essentially nonsense. First off, no one shoots an "open bolt" rifle in any sort of target competition, and that comes from the simple fact there are no open-bolt target rifles.

There's damned few open-bolt rifles, period, and all of those, as noted earlier, are one form or another of machine gun.

You stated at least twice:


it just makes sure there is no "blowback" or other means of lost energy, such as gas cocking mechanisms....


they want to be able to get they bullet out there with every bit of the energy from their gunpowder as possible.

... That the primary reason for a "closed bolt" is to put the maximum amount of energy in a bullet, particularly at extended ranges.

And that's not necessarily the case. Yes, the cartridge needs to be fully sealed to the breech to prevent gas leakage, but again, ALL guns fire when the breech is closed, so the distinction is pointless and irrelevant.


i think i'm going to design a sabot-shaped paintball and loading system tonight.--- wish me luck producing those projectiles... lol

It's been done: machined teflon sabots to fit a paintball to a "Paradox" rifled shotgun barrel (and fired with a Nelson valve, as I recall.)

I didn't see it myself, only heard of it second hand, but the bottom line was that there was no improvement in accuracy.

If you're going for maximum velocity the sabot system might have some use, but naturally, you can't play a game at anything above 300 fps. Still might be interesting to see how fast you can push a ball before it explodes in flight like a .17 Fireball. :D

Doc.

[moballs]

nerobro and FallnAngel are defently correct in that paintballs dont act as bullets do The reason rifleing helps real snipers is because spinning the cone shaped bullet keeps areas of unequal pressures from building up on different sides of the bullet (similer to vortex shedding on a sphere) the reason snipers use single shot closed bolt action is because it holds more psi behind the bullet while in the barrel.
oh yea when a paintball spins the shell does most of the spinning because the Polyethelyne glycol is, of course, a liquid in side the hard gellatin shell

[No sKiLLz]

Um. I thought we were talking about paintball?

Can the mag bolt even cause the paint to roll in the breech? The friction of the ball and the bottom of the breech would have to overcome the friction between the bolt and the ball, and since there is considerably more force on the ball from the bolt than from gravity, the bolt should win.

[trains are bad]

the reason snipers use single shot closed bolt action is because it holds more psi behind the bullet while in the barrel

Oh man...this is just a nugget.. there is so much firearms BS being spewed in this thread my office is starting to stink.

*Addressed to AO*

Please do not offer advice to someone on something you know nothing about.

Thanks for attempting to set them straight doc (and others)

This is my favorite so far:


The other reason that snipers use the closed bolt, *as opposed to the nonexistent 'open bolt' apparently* bolt action is for silence. It allows them to very quietly, and on their own terms remove a spent cartridge and load a new one. With a semi auto, it would re-chamber this cartridge automatically, which could give away the snipers position by either sound and/or visibility

[Chris42050]

This thread is very interesting even if it is off topic. I havent read a reason WHY they make sniper rifle's single shot. There must be a reason it is loaded the way it is. All that I have read says they usually only make single shot sniper rifle's. WHY? Its not by accident. If they could load faster and have the same accuracy, range, etc. then they would.

P.S. I read thru this thread quickly so I may have missed someones explanation.

[DeeEight]

Originally posted by Magluvr
Ok....

So essentially if the bore was loose enough on the ball, it wouldn't stop the roll, and actually cause the ball's trajectory down range to drop more than it should.

Except....

#1 With most every open bolt marker I've ever seen, the gas isn't actually released until the bolt has shoved the ball into the breech/reached the end of its travel. So the speed at which it might be rolling is MINOR compared to how fast its about to be accelerated up to. Flatline barrels impart the backspin by rolling a ball along the upper surface of the entire length of the barrel while its accelerating under gas pressure.

#2 If the gun has any kind of anti-double feed involving a single contact point in the breech (side nubbins, detent ball, etc, anything other than an o-ring surrounding the whole breach/barrel), then the ball would be most likely to catch on it when being pushed by the bolt and spin in whatever direction the anti-double feed was. So if its on the left, it'd tend to be a left spin. Except there's been zero evidence of guns with left side ball detents only arcing left in flight.

#3 Its going to have to be a REALLY smaller paint to barrel bore for it to keep a spin going in whatever direction it started. The Galactic Systems Z-body for the Mags had a small adjustable nubbin, but in most all Mag reviews, if the testers didn't use a really overbore barrel, what resulted was at most 10 to 20 feet more range (vs the 100 feet more range M98 owners were getting from flatline barrels). Lapco actually made a Z-barrel version of the bigshot in a .697" bore, just for the Z-body, to ensure good backspin down the barrel for the ball.

The only bolts that actually produce backspin are things like the Cooper-T better bolts, and even then, you still need smaller paint than the barrel to maintain the backspin.

[DeeEight]

Originally posted by Chris42050
This thread is very interesting even if it is off topic. I havent read a reason WHY they make sniper rifle's single shot. There must be a reason it is loaded the way it is. All that I have read says they usually only make single shot sniper rifle's. WHY? Its not by accident. If they could load faster and have the same accuracy, range, etc. then they would.


The most fundamental reason had always been that most bolt-action rifles were better made than gas-action designs, had heavier barrels, better stocks, etc. Plus they usually chambered a much heavier caliber. Several countries use a gas-action design though. The russian SVD is a prime example, as well as the Israeli Galil Sniper rifle, or the american M21 (which is a version of the M14), and yugoslavia had the M76 (which is similar to the SVD but is usually used in the old german 7.92mm caliber instead of the old russian 7.62x54R cartridge).

[Chris42050]

still confused why they are better Deeeight. Cant these countries just make a gas powered gun thats just as good or is there a reason they cant?

[bryceeden]

They could, but it would cost alot more. There are several good semi-auto sniper rifles like the WA-2000 and such, but in general they cost more than they are worth.