Closed v. Open (Bolt)

[billmi]

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]

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]

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]

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]

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.

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.

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

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

Bill has the right example.

[SlartyBartFast]

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.

[Treghc]

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

[_Spork_1]

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]

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]

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]

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]

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]

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]

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]

viking v/s excal

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