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Thread: Closed v. Open (Bolt)

  1. #31
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    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.
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  2. #32
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    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.
    WDP: "Our gun is $400 shinier than yours." - Miscue

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  3. #33
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    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.

  4. #34
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    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.

  5. #35
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    Still wondering...

    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
    Butchering spelling one word at a time.

  6. #36
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    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.

  7. #37
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    yea...

    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.

  8. #38
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    "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.
    Last edited by BlackVCG; 01-23-2002 at 07:22 PM.

  9. #39
    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
    Greets Manuel
    .:| levelx retro z-minimag |:..:| spearhead #192 |:.
    .:| ---> looking for Flatline 4.5K or AA Apokalypse 2K <--- |:.

  10. #40
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    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
    WDP4LIFE

  11. #41
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    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.

  12. #42
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    Since this is deep blue after all... I figured I might mention some physics

    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!
    Attached Images Attached Images

  13. #43
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    HAHAHA...

    I can get a brain wave to micro switch adapter at Walmart right?

    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

  14. #44
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    no arguments

    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!

  15. #45
    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
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  16. #46
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    The ball leaves the barrel in about 3 thousandths of a second. This is long before the gun starts moving anywhere.

    AGD

  17. #47
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    Great minds think alike, eh Tom? ;-)

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

  18. #48
    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

  19. #49
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    Re: HAHAHA...

    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.)
    my 98custom is for my calculated shots...mags are for insertion and extraction and pretty much everything else from sniping

  20. #50
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    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.

  21. #51
    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

  22. #52
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    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?

  23. #53
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    Question Open vs. closed accuracy

    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?
    Man with one chopstick, go hungry.

  24. #54
    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?

  25. #55
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    i gotz a question

    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
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  26. #56
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    i think the only thing that can reduce precoil and recoil is the superbolt due to its lightweight nature.

  27. #57
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    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.
    Dark Cocker.
    Apocalypse 2k2 88cui 4500psi tank.

    Old Automag with a hyper frame for fun.

  28. #58
    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.

  29. #59
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    rifling paintguns

    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.

  30. #60
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    um...little more research plz

    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.
    oh hey its 3:15 time for cake and sodomy! (name that comic strip if you can!)

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