smaller always better? , .684 vs. .688

[GoatBoy]

I haven't sifted through all of your data, but have you ever done a run of 100 and chrono'd every shot?

[cockerpunk]

There is a possible trend going on in those tests, but unfortunately the sample size per run is too small to be conclusive.

same sizes are 20+ shots each, more then large enough.

we have tons of data, as we also collect velocity on every shot we shoot in every test, so there is more then enough data. the control bore tests we later did show the exact same trend.

link to all the data: http://punkworkspaintball.com/index.php?p=2

[GoatBoy]

There is a possible trend going on in those tests, but unfortunately the sample size per run is too small to be conclusive.

[cockerpunk]

What I'm struggling with is one underbores to remedy inconsistencies in paint, but one must use that same inconsistent paint to determine which bore size to use. This can be applied to overboring as well.

If the blow-by is inconsistent if attempting to overbore, and the drag is inconsistent when attempting to underbore, does it truly make a difference?

What about coefficient of friction between a constant barrel and inconsistent paint? What about the ball deforming when the air blast hits it? Would that increase the seal of an inconsistent paintball within the barrel similar to an oring deforming into a seal when pressure is applied? Should we therefore aim for a -.001" underbore to +.001 overbore to get maximum seal, but minimum drag?

So many variables (especially when measuring to thousandths of an inch on gel capsules), but the only constant is the inconsistent paint.

Given all these and many other variables, get the paint to barrel match relatively close, and continue on the premise that paintball continues to be an accuracy by volume game.

Only exception would be for closed bolts, where the barrel is your detent, but that's a design influence not really relevant to the question at hand.

-Nathan

oldest test we did: https://spreadsheets.google.com/pub?...sMngwmAygIkHfQ

[nak81783]

What I'm struggling with is one underbores to remedy inconsistencies in paint, but one must use that same inconsistent paint to determine which bore size to use. This can be applied to overboring as well.

If the blow-by is inconsistent if attempting to overbore, and the drag is inconsistent when attempting to underbore, does it truly make a difference?

What about coefficient of friction between a constant barrel and inconsistent paint? What about the ball deforming when the air blast hits it? Would that increase the seal of an inconsistent paintball within the barrel similar to an oring deforming into a seal when pressure is applied? Should we therefore aim for a -.001" underbore to +.001 overbore to get maximum seal, but minimum drag?

So many variables (especially when measuring to thousandths of an inch on gel capsules), but the only constant is the inconsistent paint.

Given all these and many other variables, get the paint to barrel match relatively close, and continue on the premise that paintball continues to be an accuracy by volume game.

Only exception would be for closed bolts, where the barrel is your detent, but that's a design influence not really relevant to the question at hand.

-Nathan

[Patron God of Pirates]

Once the bolt gets past its level 10 small stem part, it will smash a ball into the breach regardless of if it wants to go or not, and then fire the contents of the ball out the front. If the ball only made it past the first detent, it is more likely a result of the level 10 bolt spring being too strong for your velocity setting than it is that the extra friction from the underboring is halting things. It is possible that the level 10 bump is just enough to push the ball forward and allow the next one to drop into the breach.

That all makes perfect sense, but when I swapped out the freak insert for a larger (big enough to drop the paint through) one the problem went away. I came to the conclusion that the air blast escaped via the powerfeed tube.

[athomas]

Question for those who do underbore? Do you use digital calipers? The only time I tried underboring the first ball only made it past the detent, The next ball engaged my LV.10 so I was fully jammed up. I've always used the paint to barrel matching technique outlined above by athomas and had (empirically) good results.

Once the bolt gets past its level 10 small stem part, it will smash a ball into the breach regardless of if it wants to go or not, and then fire the contents of the ball out the front. If the ball only made it past the first detent, it is more likely a result of the level 10 bolt spring being too strong for your velocity setting than it is that the extra friction from the underboring is halting things. It is possible that the level 10 bump is just enough to push the ball forward and allow the next one to drop into the breach.

[cockerpunk]

Lol. Way to quote only the part of my statement that supported this. You missed "Granted, greater consistency makes it easier to predict the flight path of your paint."

Question for those who do underbore? Do you use digital calipers? The only time I tried underboring the first ball only made it past the detent, The next ball engaged my LV.10 so I was fully jammed up. I've always used the paint to barrel matching technique outlined above by athomas and had (empirically) good results.

i undebrore on my cocker threaded mags, but i also don't tune my level 10 that hot. i already explained how i select my bore size.

works great, i can squeeze 1350 out of a 68/45 on a soft fill with a nice underbore. thats almost reasonable efficiency!

[dboggs79]

I had to...lol

[Patron God of Pirates]

How could you possibly believe this? Efficiency and consistency is directly tied to accuracy. Muzzle speed helps to dictate accuracy and you can even go so far to show that if improperly sized the paint will wobble in the barrel further decreasing accuracy.

Lol. Way to quote only the part of my statement that supported this. You missed "Granted, greater consistency makes it easier to predict the flight path of your paint."

Question for those who do underbore? Do you use digital calipers? The only time I tried underboring the first ball only made it past the detent, The next ball engaged my LV.10 so I was fully jammed up. I've always used the paint to barrel matching technique outlined above by athomas and had (empirically) good results.

[cockerpunk]

Something being accurate is not the same thing as being precise.

someone ALWAYS brings this up ... haha

for the purposes of paintball, accuracy and precision are interchangeable. this is because the aim point is easily changed.

this is not like a measuring system or device where there is a true value we are trying to hit, that "true value" is the aim point of the gun, and easily movable.

to bring up an example, if i had a target out at 30 feet, i could take the exact same setup and shoot it, and get zero hits (0% accuracy) and i could shoot it and get every one to hit (100% accuracy). only by moving the aim point. this doesn't mean in paintball terms that the setup has multiple accuracies, it means i have bad aim.

[dboggs79]

Something being accurate is not the same thing as being precise.

[cockerpunk]

No, I mentioned that the best consistency is if the ball touches on both sides of the ball but it depends on consistent paint. That is paramount. It takes much less energy to pop that cork as well, which makes it very efficient.

If you are talking inconsistent paint, then that is where we either underbore or overbore for increased consistency. I think we are talking the same language but you are interpreting my writing a bit differently. I suspect we are interpreting the amount of touch differently. What I interpret as the right amount of ball touching, you might be interpreting as a couple of thousands of underbore, in which case we are on the same page.

I remember back in 1990 when we were using PMI premium and were shooting barrels that were 0.690". The paint was popping like a cork and flying all over the place with no predicability. I was one of the only ones that had a barrel with known id sizes, and changed to a near perfect match at 0.6925". The balls flew perfect and consistent every shot. We checked the paint and found it to be consistent from ball to ball, so underboring by even 0.0025" was not working for us at that time.

As a personal preference, I like to overbore because I have less barrel breaks. This is even when I have sized the barrel for my paint. It is the one or two odd shaped balls in a bag of 500, that could cause a problem. I prefer not to take a chance when in a tournament environment and goo in my barrel could be the difference between winning and losing due to a missed shot.

ALL paint is inconsistent. not only in its size, but also in how it is loaded, the orientation of that ball matters greatly to drag. paint to barrel is always going to be the worst for consistency because of this.

paint to barrel match has less friction, yes, but it also has a lot of leakage. this is why under-boring is much more efficient, yes there is more friction, but it makes a much better seal.

we describe paint to barrel match as the same thing, the blow test match ... so we are not talking about the same thing.

underboring, or paint to barrel match does not increase the frequency of barrel breaks until you get down to extreme underbores. that is old thinking, long been overturned. if you are getting barrel breaks, look at your loader, and look at your bolt.

[cockerpunk]

How could you possibly believe this? Efficiency and consistency is directly tied to accuracy. Muzzle speed helps to dictate accuracy and you can even go so far to show that if improperly sized the paint will wobble in the barrel further decreasing accuracy.

up to about a 15 fps spread, consistency does not effect accuracy.

[athomas]

that is actually the worst for consistency. and its because of inconsistently sized paintballs. we underbore exactly because paint is not consistent.

No, I mentioned that the best consistency is if the ball touches on both sides of the ball but it depends on consistent paint. That is paramount. It takes much less energy to pop that cork as well, which makes it very efficient.

If you are talking inconsistent paint, then that is where we either underbore or overbore for increased consistency. I think we are talking the same language but you are interpreting my writing a bit differently. I suspect we are interpreting the amount of touch differently. What I interpret as the right amount of ball touching, you might be interpreting as a couple of thousands of underbore, in which case we are on the same page.

I remember back in 1990 when we were using PMI premium and were shooting barrels that were 0.690". The paint was popping like a cork and flying all over the place with no predicability. I was one of the only ones that had a barrel with known id sizes, and changed to a near perfect match at 0.6925". The balls flew perfect and consistent every shot. We checked the paint and found it to be consistent from ball to ball, so underboring by even 0.0025" was not working for us at that time.

As a personal preference, I like to overbore because I have less barrel breaks. This is even when I have sized the barrel for my paint. It is the one or two odd shaped balls in a bag of 500, that could cause a problem. I prefer not to take a chance when in a tournament environment and goo in my barrel could be the difference between winning and losing due to a missed shot.