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Thread: Paint to Barrel match testing

  1. #1
    Join Date
    Sep 2004
    Posts
    1,144

    Paint to Barrel match testing

    Quote Originally Posted by brycelarson View Post
    Hey everyone, CockerPunk and I did another barrel test.

    I became curious while reading Mann's barrel test on PBN about a few things.

    1. What sizer is optimal for a particular ball
    2. What effect does drastic over and under boring have on efficiency and consistency

    Our test rig was the following:
    * emag
    * shooting chrony (accurate to %99.5)
    * 500 anarchy paintballs (pretty fresh mid-grade paint)
    * bucket

    I shot 20 shots through the chrony from each of the following:
    * freak kit (12 inches with teardrop front) all 10 inserts - we had a couple of duplicate sizes
    * CCM carbon fiber kit - 5 backs
    * 4 random cocker threaded barrels we had sitting around including 2 identical Dye 12" aluminum boomsticks

    We recorded velocity from each and the results are posted in the following spreadsheet:

    http://spreadsheets.google.com/pub?k...sMngwmAygIkHfQ

    Our results indicate that the smallest barrels / inserts / backs had both the highest average velocity and the lowest standard deviation. This test would indicate to me that if given the choice under-boring is your best bet.

    I don't know the implications for barrel break increases with fast shooting - that would take another pile of paint and some more testing.
    heres my take on the test we did -

    indeed, it seems that "perfect" paint to barrel match is actually the worst from a performance aspect.

    heres our theory about why -

    when you overbore, the ball rarely, or at least touches the barrel less, and thus, the variation in size from paintball to paintball means less. this means that air leaks around it (thus the worse efficiency), but also that the gun is more consistent due to a more consistent force from the barrel on the ball. more accurately, the variation in size of the ball does not have a huge effect on the force the barrel imparts on the ball (both directionally and velocity wise).

    when you under bore, obviously you get more shots per tank, becuase less air leaks out. and the barrel imparts a consistent force becuase every single ball is to large, and thus the force is more constant. again, the variation in shape and size of the paintball has less effect on the force the barrel imparts becuase all the balls are being squished more or less equally.

    and it seems that "ideal" paint to barrel match is not ideal in the least. you have to pay the efficiency cost from the air leakage, and you get inconsistent forces from the barrel becuase some of the balls touch more than others.

    so, from this it seems that a bit underbored is probably the best, but a bit operbored is almost as good. both monster over and under bored hurts performance, and as stated before, "perfect" is the worst of both worlds.

    yes, a barrel break test might just be in the works when we talk about underboring.

  2. #2
    Join Date
    Jan 2006
    Location
    Not In Seattle
    Posts
    2,095
    Quote Originally Posted by cockerpunk
    heres my take on the test we did -

    indeed, it seems that "perfect" paint to barrel match is actually the worst from a performance aspect.

    heres our theory about why -

    when you overbore, the ball rarely, or at least touches the barrel less, and thus, the variation in size from paintball to paintball means less. this means that air leaks around it (thus the worse efficiency), but also that the gun is more consistent due to a more consistent force from the barrel on the ball. more accurately, the variation in size of the ball does not have a huge effect on the force the barrel imparts on the ball (both directionally and velocity wise).

    when you under bore, obviously you get more shots per tank, becuase less air leaks out. and the barrel imparts a consistent force becuase every single ball is to large, and thus the force is more constant. again, the variation in shape and size of the paintball has less effect on the force the barrel imparts becuase all the balls are being squished more or less equally.

    and it seems that "ideal" paint to barrel match is not ideal in the least. you have to pay the efficiency cost from the air leakage, and you get inconsistent forces from the barrel becuase some of the balls touch more than others.

    so, from this it seems that a bit underbored is probably the best, but a bit operbored is almost as good. both monster over and under bored hurts performance, and as stated before, "perfect" is the worst of both worlds.

    yes, a barrel break test might just be in the works when we talk about underboring.
    I always get the 'nice fit', then pick the back that's one bore size larger. I always seem to get barrel breaks with the 'nice fit'.

  3. #3
    Quote Originally Posted by cockerpunk
    heres my take on the test we did -

    indeed, it seems that "perfect" paint to barrel match is actually the worst from a performance aspect.

    heres our theory about why -

    when you overbore, the ball rarely, or at least touches the barrel less, and thus, the variation in size from paintball to paintball means less. this means that air leaks around it (thus the worse efficiency), but also that the gun is more consistent due to a more consistent force from the barrel on the ball. more accurately, the variation in size of the ball does not have a huge effect on the force the barrel imparts on the ball (both directionally and velocity wise).

    when you under bore, obviously you get more shots per tank, becuase less air leaks out. and the barrel imparts a consistent force becuase every single ball is to large, and thus the force is more constant. again, the variation in shape and size of the paintball has less effect on the force the barrel imparts becuase all the balls are being squished more or less equally.

    and it seems that "ideal" paint to barrel match is not ideal in the least. you have to pay the efficiency cost from the air leakage, and you get inconsistent forces from the barrel becuase some of the balls touch more than others.

    so, from this it seems that a bit underbored is probably the best, but a bit operbored is almost as good. both monster over and under bored hurts performance, and as stated before, "perfect" is the worst of both worlds.

    yes, a barrel break test might just be in the works when we talk about underboring.
    I've always figured this might be the reason that Palmer's barrels with the elliptical honing shoot so well:
    -Tighter at the beginning where the ball isn't moving fast and the air is at its highest pressure so more gas is going to be wasted if there is extra space around the ball.
    -Looser in the middle of the barrel where if the ball is touching unevenly it's going to pick up most of it's spin. Lower gas pressure behind the ball due to expansion and the fact that by the time it's halfway down most barrels it's done most of it's acceleration mean that gas wasted to the looser fit will have less effect on overall efficiency.
    -Tighter again at the tip to guide the ball while minimizing time in contact with the ball to minimize the spin it can pick up.

    That's my take on it anyway.

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