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Thread: The scientific method for determining the effects of open vs closed bolt

  1. #1

    The scientific method for determining the effects of open vs closed bolt

    Purpose: To determine whether firing method has any effect on the trajectory and drop of paintballs being shot.
    Hypothesis: If the laws of physics are true, then there will be no effect on the trajectory, or drop of the paintballs.

    Materials:




    Two paintball guns, one using the open bolt method of firing and the other closed

    A high grade barrel, one that is accurate, barrel kits could also be used but it would be best to just use one barrel that matches the paint

    A sturdy bench mount capable of holding the gun without changing position between shots.

    Laser level that can send a beam along a wall

    Accurate chronograph

    Good video camera, the higher the fps the better, also mounted in a constant position for each test to eliminate different points of view causing confusion

    High grade paint

    Reballs- the consistency of these should help eliminate some variables

    A target with coordinates on it, that can be easily cleaned between shots

    Laser pointer that is penlike(cylinder) and has a switch that allows it to stay on without being touched.

    probably more stuff but i dont know, will add later



    Procedure:
    1. Indoors, set up the first gun in a vice. Aim it at the target with the coordinates on it and calibrate by setting the laser pointer in the barrel while its on and letting it settle in the barrel, providing its unobstructed it will align down the center of the barrel allowing the calibration of the gun to the center of the target. Then using the laser measure that can put a beam down a wall, center this so that it runs along the x axis of the gun, seperating the barrel evenly in two to assure that the gun is level, also checking that the height from the center of the barrel matches with the height at which the laser meets the wall with the target. Assuring that the gun is level is key to the accuracy of the experiment.
    2. Set up the camera in a sturdy tripod or other type of mount. This will be perpendicular to the line of fire of the gun and should be kept in a constant position for trajectory determinations to eliminate the errors from different points of view. Zoom the camera in so it includes the gun and the target in the opposing edges of the field of view.
    3. Now that the gun is level it is important that it is not disturbed, do not disturb the surface it is mounted on. All adjustments should now be made to the target itself. The target should have the x axis along the same level as the barrel, and the laser coming from the center of the barrel should hit at the origin of the target.



    Procedure Part 2
    Shooting:
    1. The gun is now fully calibrated to the target and you can begin shooting using the high grade paintballs following this method.
    2. The hopper could be gravity fed with a few balls being loaded at a time, making sure to make minimal hand contact with the paintballs, as not to affect them.
    3. Using the accurate chronograph setup in the same position beneath the barrel to avoid giving different readings for velocity.
    4. Start the camera recording.
    5. With the paintball gun loaded with a paintball in the chamber, the first shot can be fired, it is imperative to record the velocity for every single shot, along with the coordinates on the target and then write them down in a table of some sort. Clean the paint off of the target after each shot. Having another person helping would be convenient at this point.
    6. Repeat this for as many shots as you can endure writing, and cleaning, writing and cleaning. The more shots taken give a better average overall and will lead to your results being more credible. Stop filming when all testing has been completed, making sure that it records fully through to show that no tampering had taken place
    7. You can then follow this procedure for the other gun, keeping the parameters as close as possible, and making absolutely sure that the barrel of the second gun is level.



    Calculations: Now you should have a large amount of data with coordinates corresponding to different velocities. The important coordinate is the Y values correspond to each different velocity, which can be averaged or plotted, it would be wise to eliminate shots that have gone to the side, outside of the main grouping for the average because they were most likely influenced by spin and could give mixed results on the height. However, it is important, if plotting the data on a graph to have all the shots to show the overall accuracy of the gun, because a closer overall grouping adds to the credibility of the results. Also, the video footage can possibly be used to observe the trajectory and compared with shots at the same velocity with the other gun (this is why it’s important not to move the camera). With the two sets of data you can now conclude whether the average drop of the paintball at each different velocity is larger or smaller for each paintball gun. The experiment can not yield results that do not provide a valid conclusion, providing that the two guns were setup identically. There are three possible conclusions to be drawn:
    1. One firing method shows a noticeable advantage over the other in the amount of drop for paintballs fired from each gun.
    2. There is no discernable difference in the amount of drop for paintballs fired from each gun.
    3. The paintballs were too inaccurate to draw any conclusive results between the amounts of drop for each gun, which leads to the conclusion that paintballs are inaccurate enough to void any effects provided by the firing method and it does not matter which method of firing your gun uses. (If this experiment is done with high quality paintballs this statement is further proven because it can be assumed that most paintballs used in real world situations are of lesser quality and thus suffer further from the effects of inaccuracy).

    I spent hella days writing this.
    You better watch yo' self B!

  2. #2
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    Quote Originally Posted by ProX9
    I spent hella days writing this.
    So are you going to do it?

    WARPIG already did a fairly conclusive test by converting a Stingray between open and closed bolt operation.

    But, the die-hard believers will still doubt the results. Glenn Palmer insists that closed bolt is better regardless....

  3. #3
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    You can simplify your data taking a little. Since you're not concerned with individual shots (which would be foolish as there are too many variables between paintballs, air density, etc.) and are going to be taking averages anyhow, just collect the average to begin with.

    Use a piece of plywood or similar porous surface as a target. Make sure it is braced firmly enough not to shake or wobble when hit and ensure that the paint strikes it perpendicularly. It needs to be porous so the paint does not run down it as much as it would if you used something like a whiteboard.

    Fire groups of 10 or 20 shots and record the overall diameter of the resulting mark. We can assume that over a great deal of testing, abnormalities in the splatter will balance out. With about 100 rounds from each marker (cleaning the barrel thoroughly between 10-shot groups), you'll get a decent average splat diameter.

    Alternatively, you can use reballs with a piercable target. A piece of aluminum foil held tightly at all corners might work well. Make sure that it is held firmly and keep in mind that only high velocities will give you decent break-through.


    Don't worry about ball drop and trajectory. Those things are not what you're trying to calculate and are a result of end velocity only unless there is some sort of backspin device used. Concern yourself only with spread size and pattern. Keep in mind that you'll need to truncate your results by dropping the lower and higher numbers to get a reliable mean.


    You're looking for small groupings with few 'fliers' in order to determine the best 'accuracy'.



    HOWEVER - keep in mind that any benefits of a closed-bolt system are mitigated once you exceed about 10 bps. The bolt is moving so fast anyhow, it doesn't really matter whether it's open- or closed-bolt.

    Good Luck!
    Before: "You're playing with WHAT?"
    After: "Crap! It's that guy with the pump!"

  4. #4
    I actually am concerned with individual shots, as long as I have a velocity to associate each impact position of a ball I can basically see what would happen if my guns velocity never fluctuated at all. All I have to do is get an an average drop for each different velocity and then I can compare results. I would also plot the impact data on a graph which would be the same as the target, so i have the benefit of both averages.

  5. #5
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    The variances that occur firing a paintball:
    1) out-of-round paintball to paintball variation
    2) shot-to-shot velocity differences
    would swamp any differences that would be caused by the bolt configuration.

  6. #6
    CaliMagFan Guest
    Quote Originally Posted by deadeye9
    The variances that occur firing a paintball:
    1) out-of-round paintball to paintball variation
    2) shot-to-shot velocity differences
    would swamp any differences that would be caused by the bolt configuration.

    solved by... use of reballs... and chronoing each shot fired...

    remember, this is an experiment to find if one is really better than the other. It's not really a super-real world scenario.

  7. #7
    I dont even have to use re-balls since id be shooting enough shots to be able to eliminate outliers and still have a large number of shots to base my data off of. The velocity differences are also negated because id only be grouping the results from each different velocity, eg only the coordinates for shots that went 288 fps would be used to compare with the other gun's shot's that went 288 fps. Please read the actual experiment and then the meaning of each part before you criticize, suggest, or post anything pertaining to it.

  8. #8
    CaliMagFan Guest
    Quote Originally Posted by ProX9
    I dont even have to use re-balls since id be shooting enough shots to be able to eliminate outliers and still have a large number of shots to base my data off of. The velocity differences are also negated because id only be grouping the results from each different velocity, eg only the coordinates for shots that went 288 fps would be used to compare with the other gun's shot's that went 288 fps. Please read the actual experiment and then the meaning of each part before you criticize, suggest, or post anything pertaining to it.
    your projectile will be "consistent enough" if you do eliminate the clearly extraneous ball or 2... but the use of reballls would be more scentifically correct, cause the projectile is still a variable.

  9. #9
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    Or you could get these things called "Perfect Rounds" which are often used in accuracy tests by companies that make paintball guns for things other than paintball (like Pepperballs). Perfect rounds are plastic shelled .68 cal "paintballs" that are filled with water and are supposed to be the best thing out there for consistantly spherical paint.

    This sounds like overkill, but hey, I'm curious and if its overkill, that's generally a good thing. Have Fun!

    Physics don't lie

  10. #10
    Ill be using good paintballs, another point to this test is to see if actual paintballs can be used and still show a discernable difference despite the inherent problems with using actual paint. Make sense?


    3. The paintballs were too imprecise to draw any conclusive results between the amounts of drop for each gun, which leads to the conclusion that paintballs are imprecise enough to void any effects provided by the firing method and it does not matter which method of firing your gun uses. (If this experiment is done with high quality paintballs this statement is further proven because it can be assumed that most paintballs used in real world situations are of lesser quality and thus suffer further from the effects).

  11. #11
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    yeah, I saw that, I was following up on the guy above me who sudgested ReBalls.

  12. #12
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    It's really late, and I need some sleep. So instead of rambling on about physics, I will say; you forgot to include the atmospheric pressure readings, density of paintball..... must sleep.

  13. #13
    Welcome back to 1998...
    My AIM Intimidator is better than your Automag. Get over it.
    Hobart Paintball AIM Paintball

  14. #14
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    Good idea.

  15. #15
    i was thinking latley about why everbody says closed bolt is more accurate and i might have come up with a reason this is said. It may sound stupid but its just a thought. Here it is: the ball is shot millseconds before a open bolt shoots because it does not have to wait or the bolt to come, this would make there shots go closer to a moving target or while you are moving go closer to where you want it to( i know this could be fixed by knowing shoot were there going but people who think they are more accrate are not informed and probably ouldnt be informed about that either), But closed bolts will not have straighter shoots more range or accuracy everytime this comes up it is proven that they are the same with the same results.

  16. #16
    For your test marker why wouldn't you use a mechanical cocker that you swtch from closed bolt to open bolt. That way you would get rid of many variables such as consistency being different from marker A to maker B. To do so you only need to reverse the timing and the hses going to the ram. Usually the first action when you pull the trigger is to release the hammer and then activate the ram but you would get ram and then sear. 2 test markers ll in one

  17. #17
    *edited*
    Last edited by 93civiccpe; 04-07-2005 at 07:42 AM.

  18. #18
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    Quote Originally Posted by 93civiccpe
    A quote that I love to tell people is that it is better to have people think you a fool, then to open your mouth and confirm it. Don't waste your breath on stupid arguements like this.
    You should listen to it yourself. Change your tone and drop the grammar Nazi bit.

    The very existence of Deep Blue is so that technical questions aren't just "dropped" or ignored and to explore ways to prove or disprove theories.

  19. #19
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    Quote Originally Posted by SlartyBartFast
    You should listen to it yourself. Change your tone and drop the grammar Nazi bit.

    The very existence of Deep Blue is so that technical questions aren't just "dropped" or ignored and to explore ways to prove or disprove theories.
    I couldn't agree with you more. How unnecessary would this forum be if everyone just dropped thier idea's. I get kind of sick of seeing posts where people enter a thread and then try to make everyone stop discussing the thread topic.

  20. #20
    Sorry, I wasn't trying to make someone end the thread or stop talking. Johnson88, I apologize on the grammer thing but I had to read it a few times just to try to understand what they were saying, and I got somewhat annoyed. I will handle that differently in the future. There is just already a lot of research out there about this. Plain and simply when it comes to being a real-life military sniper, one of the most important factors is the rifling in the barrel to make sure the bullet is spinning correctly, and also the ammo itself. The ammo has to be the correct size, shape, & weight to have accuracy at different distances. A paintball has a liquid inside it, so by spinning it you don't get the same effect. Actually, if you have any sort of dimple or if the paintball is not completely round then spinning the paintball can cause unwanted hooks. The armson barrels have been tested to see if the rifling helps and even though I love those barrels, they were shown to be no better than other high-end barrels which did not have rifling. The ammo and the barrel are two of the most key elements in making a gun accurate. Both a good closed bolt and a good open bolt marker can apply a constant pressure source on the paintball which is what matters. There are some advantages and disadvantages to both but they really don't affect accuracy. I think we need to start with innovating the paint and barrel first if we are going to try to improve accuracy.

    As for you slarty, I guess you find some odd joy in challenging me and thank you for the "nazi" comment. You are very mature. And you are not an admin so don't command people people as to what to do in a forum you have no control over. If I want to criticize someone because their post is so full of slang/ebonics that I cannot read it, then I will. My problem with the misspellings are that he put it in the forum which is labeled "Named after the IBM super computer, Deep Blue is headed by Tom Kaye, president of AGD. This forum is open to the public, but only high end technical subjects are allowed. If your posts don't cut the mustard they will be moved." My problem was that he posted in a technical forum and it was in very bad english/slang. On top of that, I honestly still don't know if I understand what he is actually trying to say. If he did some research I'm sure he would get his answers as there have been a lot of tests done on this subject. I apologize if I upset or offended anyone but I edited my other post out so no one else will see it and think I'm harassing you Johnson.
    Last edited by 93civiccpe; 04-07-2005 at 08:58 AM.

  21. #21
    Yes switching a cocker to open bolt is easy but it takes time your best bet would be to take any open bolt marker that has a pull pin pull it and slide the bolt forward the gun will still shoot and you just hold the bolt forward thats closed bolt want it open pop the pin right back in.

  22. #22
    If I were to do this, the reason I wouldnt want to switch the gun from open to closed so I could use the same gun is because thats not an actual representation for that bolt type, I dont want to say that an open bolt autococker doesnt shoot as far or the same because that has no real bearing in reality, and I know the test isnt perfect reality but I think that comparing actual open vs closed (viking vs excal) would give it more reality.

  23. #23
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    sooooo many variables. open-vs-closed bolt accuracy.

    shape of the paintballs.....weight of the paintballs.....variables......ballistic coefficient.....etc etc etc.

    Interesting topic, but so so so old.....might be time to give it a rest.

  24. #24
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    Quote Originally Posted by ProX9
    Hypothesis: If the laws of physics are true, then there will be no effect on the trajectory, or drop of the paintballs.
    Not sure if anyone's mentioned this yet but that's a pretty unscientific hypothesis.

  25. #25
    Is an exirement such as this really needed? honestly, both open and closed bolt use a bolt and thereby impact the ball with comparable velocities and deform it in much the same way. they both have a flow through bolt, a spring/ pnumatic ram with similar force. Honestly most of what differs in the internals of the guns is sequence.

    The only real possible differance in accuracy and the like is that in open bolt the ball is deformed when propeled by the air and in closed bolt the ball is more of a ball because it has had time to spring back.

  26. #26
    Quote Originally Posted by J_Hoyt
    Not sure if anyone's mentioned this yet but that's a pretty unscientific hypothesis.

    how so?

  27. #27
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    Quote Originally Posted by 93civiccpe
    Sorry, I wasn't trying to make someone end the thread or stop talking. Johnson88, I apologize on the grammer thing but I had to read it a few times just to try to understand what they were saying, and I got somewhat annoyed. I will handle that differently in the future. There is just already a lot of research out there about this. Plain and simply when it comes to being a real-life military sniper, one of the most important factors is the rifling in the barrel to make sure the bullet is spinning correctly, and also the ammo itself. The ammo has to be the correct size, shape, & weight to have accuracy at different distances. A paintball has a liquid inside it, so by spinning it you don't get the same effect. Actually, if you have any sort of dimple or if the paintball is not completely round then spinning the paintball can cause unwanted hooks. The armson barrels have been tested to see if the rifling helps and even though I love those barrels, they were shown to be no better than other high-end barrels which did not have rifling. The ammo and the barrel are two of the most key elements in making a gun accurate. Both a good closed bolt and a good open bolt marker can apply a constant pressure source on the paintball which is what matters. There are some advantages and disadvantages to both but they really don't affect accuracy. I think we need to start with innovating the paint and barrel first if we are going to try to improve accuracy.

    As for you slarty, I guess you find some odd joy in challenging me and thank you for the "nazi" comment. You are very mature. And you are not an admin so don't command people people as to what to do in a forum you have no control over. If I want to criticize someone because their post is so full of slang/ebonics that I cannot read it, then I will. My problem with the misspellings are that he put it in the forum which is labeled "Named after the IBM super computer, Deep Blue is headed by Tom Kaye, president of AGD. This forum is open to the public, but only high end technical subjects are allowed. If your posts don't cut the mustard they will be moved." My problem was that he posted in a technical forum and it was in very bad english/slang. On top of that, I honestly still don't know if I understand what he is actually trying to say. If he did some research I'm sure he would get his answers as there have been a lot of tests done on this subject. I apologize if I upset or offended anyone but I edited my other post out so no one else will see it and think I'm harassing you Johnson.
    man sorry i just had to refresh this.... man this guy answered all the questions in the forum but nobody seemed to listen..... PLUS talk about shutting someone down! lol slarty dude...slarty can you say owned?!?!? lol o man this just puts a pretty grin on my face and makes me giggle.

    well on the topic of this thread.... read this dudes quote.... answers everything.

  28. #28
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    Quote Originally Posted by ProX9
    how so?
    If the laws of physics are true, then there will be no effect on the trajectory, or drop of the paintballs.
    Because you aren't testing whether the laws of physics are true. For a scientist testing something so simple, it's kinda neccessary to assume that gravity still pulls down and pi is bigger than e. Your hypothesis states that you've already made every calculation possible and neccessary to determine what will happen to a paintball - an impossible feat. Truth is, you have NO idea what the effect should be, that's what you're testing.

    If you DID find a difference between open and closed bolt, then your conclusion would have to state that "the laws of physics are not true" in order to agree with what you said in your hypothesis.

  29. #29
    Meh I think I said that more out of sarcasm because people think their guns have figured out how to defy the laws of physics. You're still right though.

  30. #30
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    Forget all of that mumbo jumbo.. Forget theories and formulas and high speed cameras.

    Get an autococker and an automag. Lock them in vises. Use one cocker barrel for both guns. A barrel that is One and the same. Fire 110 paintballs at a target out of the autococker at a rate of one or two per second. Measure the grouping of the paintballs, do not measure the worst 10 shots.
    Repeat with the automag.

    The measurement will tell all.

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