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Thread: Bore Sizing Tech Tip #2

  1. #1
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    Post Bore Sizing Tech Tip #2

    Bore Sizing Tech Tip #2

    All,

    By popular request I will divulge the inner secrets of bore/paint match ( is was 101 degrees out in the field today so I came in early)

    Does having a good paint barrel match improve your accuracy??? YES. How does it do it? Very simple, if your gun shoots with a consistent velocity the paintballs will tend to follow the same arc, thereby improving accuracy. It technically is making your gun more consistent which is a better term than accuracy.

    Historically there were many theories about paintball barrel matches. First there was the Tippman theory where they used a very large bore barrel and claimed that the air escaped evenly around the ball and it floated down the barrel without touching anything. They claimed this was the "air bearing effect". Next there was the tight barrel theory that said if the ball seals all the way around the shot will be more accurate. Actual testing has proven both these theories false.

    Why match paint to barrel? Going back in time the paintballs were much more inconsistent than they are now, in fact now they are really, REALLY round and half the price. Players found that their consistency/accuracy improved when they used certain size barrels. Unfortunately paint is constantly changing size and this requires different barrel id's to work well.

    The technique used to research paint/barrel match is simple and doable by anyone. Testing is performed by blowing a thin powder down the barrel to coat the inside. We used to use Desenex Foot Powder that sprayed on dry. Todays Desenex is a different formulation and doesn't make a powder. Once you have coated the barrel you dry fire the gun once to clear out any extra powder. Lastly shoot one paintball out the gun and inspect the inside of the barrel. The powder will be stripped away everywhere the ball touched. This allows you to see exactly what happened to the ball down the barrel.

    If the barrel is too big, the ball ricochets back and forth down the tube. We used to say it looked like Zebra stripes in there. Hence big barrels do NOT create an "air bearing". Barrels that are too small scrape most of the powder off and this creates excessive FRICTION. Tighter barrels that were too long were found to slow the balls down due to this friction. In other words, when you cut these barrels down, velocity went up. Remember the 8-10" acceleration distance, these barrels were 14" long and unported.

    The best paint barrel match left two 1/8" wide streaks opposite each other down the barrel. The widest part of a paintball is usually the seam which is also called the equator. With a proper size match only the balls equator touches the barrel snugly on two points. The equator tends not to align itself so the entire seam touches the barrel hence you only get two points touching. So what is happening here that makes this so desirable? We all know paintballs vary in size, this means that there will be slightly more or less friction on the ball depending on how tightly it fits in the barrel. If you use too tight a bore that touches the ball all around, trying to squeeze a bigger ball in greatly increases the friction and changes your velocity. By having the barrel sized to only touch two points, bigger or smaller balls only increase the contact patch a small amount and this gives you better shot to shot CONSISTENCY. To large a bore solves the friction problem but you get back to the ricochet effect.

    So this is the story behind proper paint/barrel match. Many of you have commented that the stock barrels seem to work about as good as custom barrels. This is because todays paint is so much more consistent than 10 years ago that the difference between barrels is much diminished. Even the biggest to the smallest barrels don't product that much difference in accuracy IF YOU ONLY COUNT THE SHOTS AT THE SAME VELOCITY. So there you have it, I should mention these studies were done in the early to mid nineties, we have not done any testing lately on two piece barrels etc.


    AGD

  2. #2
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    so what difference would there be if it's a stepbore? isn't it jsut the same as testing a 6 or 8 inch barrel?

  3. #3
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    This is really great information and is handy to educate others. Is it possible to archive it somewhere in this forum?
    Thanks
    -Brad

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    <font face="Verdana, Helvetica, sans-serif" size="2">Originally posted by FeelTheRT:
    so what difference would there be if it's a stepbore? isn't it jsut the same as testing a 6 or 8 inch barrel?</font>
    that is what i was thinking. what if i shot an 18 inch boomstick. wouldn't it be the same as an 8 inch unported barel (accuracy and efficiency wise), only longer and quieter?


  5. #5
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    Actually Keebler it is less efficient because you need to overcome friction for the other 8-10 inches.

    Check these points out:
    1. "Does having a good paint barrel match improve your accuracy??? YES"
    2. "Even the biggest to the smallest barrels don't product that much difference in accuracy IF YOU ONLY COUNT THE SHOTS AT THE SAME VELOCITY"

    Well in other words. The freak deffinately works but not really very well.
    That helped.
    Hitmanng

    ------------------
    "I would rather hit once than miss 140 times."

    [This message has been edited by hitmanng (edited 06-24-2001).]

  6. #6
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    what do you mean overcome the friction in the other 8 or 10 inches? i thought that the ball never touched the bigger bore sized section because it was so large. am i right or wrong on this one?

  7. #7
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    Your last statement is contradictory hitmanng.

    The Freak works because of this: "1. "Does having a good paint barrel match improve your accuracy??? YES".

    Or, I will say this, it works as well as any other barrels that is properly matched for that mater. the Freak is just another way to acheive this point number one without the expense of many barrels.

    All barrels are subject to the downfall of statement two. So there is no real reason for you to try and single out that one particular one for inclusion into that point is there?

    My point is that the Freak works as good as any barrel that is properly matched to the paint as evidenced in point number 1. That is all it claims to do. And all it will do. But in doing that, it will improve accuracy in those situaions when you are confronted with a paint that you do not have a barrel of bore size to make the closest match. With this you always have the right barrel. Thats the point. And the point of OTP and CP systems too. It works all because of the fact of statement 1. All Barrels work or don't work on that fact.


  8. #8
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    Okay we have a bit of a problem. The new RPS advantage really does have the seam tuckes into the shell. I just pulled this test on my LAPCO BS and my 14" DYE Boomstick. Hmm on the big shot I got two narrow lines that still had powder on them, according to your instructions this ball is too big. With the boomstick I got the same results except half the powder was gone and half was still there? The paint was a tiny bit swolen from leaving in the sun for 20 minutes but you couldn't notice. I used bakingflour. Does flour make a difference?

  9. #9
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    <font face="Verdana, Helvetica, sans-serif" size="2">Originally posted by hitmanng:
    Actually Keebler it is less efficient because you need to overcome friction for the other 8-10 inches.

    Check these points out:
    1. "Does having a good paint barrel match improve your accuracy??? YES"
    2. "Even the biggest to the smallest barrels don't product that much difference in accuracy IF YOU ONLY COUNT THE SHOTS AT THE SAME VELOCITY"

    Well in other words. The freak deffinately works but not really very well.
    That helped.
    Hitmanng

    </font>

    what friction? he's talking about a step-bore barrel. only 6-8 inches touches the ball, the rest is just for scielncing and dosn't touch the ball.

  10. #10
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    But that's assuming that the ball isn't making contact as it travels through the larger diameter of the stepped barrel. I would think that there would be some possibility that the ball may make contact and begin to ricochet through that larger section. The only way to be sure that a ball isn't making contact through the larger diameter section would be to powder test as Tom suggests.

    Never heard of that powder test before. Thank you Tom for letting us know about it.


  11. #11
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    Xplosive, flour should work well, if you see two thin stripes down the barrel everything is working right.

    Dogbone, yes you are right someone should check step bore barrels to see if they touch the ball in the ported section.

    AGD

  12. #12
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    That was my point Phil, according to what Tom wrote good paint to barrel match is important but do the the consistant size of paintballs and the small veriation in barrel sizes the difference may ne negligable compared to other factors on the ball.
    As far as step bore barrels. It is highly unlikely that the ball travels through them without ever touching. It is similar to the small ball in the large barrel above in Tom's example.
    Hitmanng

    ------------------
    "I would rather hit once than miss 140 times."

  13. #13
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    Ok got you now. I just didn't get why the swipe at the Freak outa your previous statement though. I mean every barrel would have that problem. So...Why single it out? Oh yea... I know...You don't got one!

  14. #14
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    Cool

    No I don't have 1. I shoot all paint with one barrel although I own two. I just have never understood the freak following. Read the freak post in the Tech forum for a full explanation. A freak will be my last if ever upgrade.
    Hitmanng

    ------------------
    "I would rather hit once than miss 140 times."

  15. #15

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    Wont the air just blow the powder out of the barrel?

  16. #16
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    Because it somewhat adheres to the inside of the barrel. Go dump a pound of white flour on your hands magboy, blow on your hands, then look at them to see if all the powder is gone after simply blowing on them Oh yeah, clean it up really quick, your mom probably wouldn't like that you dumped a pound of flour all over the floor

  17. #17
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    lol randomboy, did that once as a kid. Never was able to get it all up

  18. #18

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    lol

  19. #19

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    It Doesnt work! i just tryed flour and all that happens is it breaks paint! i even tryed blowing them out of the barrel and that didnt work either!

  20. #20
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    <font face="Verdana, Helvetica, sans-serif" size="2">Originally posted by randomboy:
    Because it somewhat adheres to the inside of the barrel. Go dump a pound of white flour on your hands magboy, blow on your hands, then look at them to see if all the powder is gone after simply blowing on them Oh yeah, clean it up really quick, your mom probably wouldn't like that you dumped a pound of flour all over the floor </font>
    Gotta be careful with flour... that stuff highly flammable if you make a cloud... accidents in the kitchen ya know...



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  21. #21
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    instead of flour... can i just use some broken paint? just a thought cuz my gun breaks paint sometimes.

  22. #22
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    I showed this page to my friend Tim who uses a Boomy. He tested it out using confectionary sugar.

    -----------------------
    Subj: boomy test...
    Date: 7/5/01 2:12:56 PM Eastern Daylight Time
    From: xxxxxxxxxxxxxxx
    To: MagDog68

    i tried that test from automags.org with my BoomStick. used confectioner's sugar. the balls left two lines down the length of the barrel in the first stage and then it looks like two dotted lines in the second stage.

    -----------------------

    Does that mean that Staged barrels are no good? I think it does...
    ~Fred

  23. #23
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    Well based on the above reply the dotted line in the second stage of the barrel means the ball is bouncing around in there. Some one else should try this too and confirm the results.

    AGD

    [This message has been edited by AGD (edited 07-07-2001).]

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