[bracer028]

When i pump, I push the pump handle forward, I feel tension when the ball enters the barrel.

Feels like I'm squeezing it too much. Would this lead to chops?

[tac0cat]

it could lead to barrel breaks, and it could lead to wild curly shots in my experience. If you have a barrel kit, take a few balls in one end of your sizers and if you cant blow the ball through its probably too small.

[senghing27]

I agree with Taco. You won't really get chops... But if you force a ball that significantly bigger than the sizer, it's going to get crushed by the bolt or break from all that force.

[drgonzo]

The previous posts are untrue, you can underbore to where you have to practically hammer the ball into the barrel and if it makes it out, it won't break or curve wildly. The point at which a ball does not make it out of a long-back barrel is about .020+ underbored, with a shorter back you can even go tighter before it won't come out.

That said, actually feeling the paint drag happens at underbores like .012+ which is not ideal. The blow test finds a sizing for almost no underbore, which is also not ideal. It should be quite difficult to blow the ball through if not impossible with an underbore.

The biggest deal about it, to me, is you want the pump stroke to be smooth, because that affects your pumping reliability and timing (avoiding chops, for example), so you might as well bore up if you feel it.

[senghing27]

Originally Posted by drgonzo

The previous posts are untrue, you can underbore to where you have to practically hammer the ball into the barrel and if it makes it out, it won't break or curve wildly. The point at which a ball does not make it out of a long-back barrel is about .020+ underbored, with a shorter back you can even go tighter before it won't come out.

That said, actually feeling the paint drag happens at underbores like .012+ which is not ideal. The blow test finds a sizing for almost no underbore, which is also not ideal. It should be quite difficult to blow the ball through if not impossible with an underbore.

The biggest deal about it, to me, is you want the pump stroke to be smooth, because that affects your pumping reliability and timing (avoiding chops, for example), so you might as well bore up if you feel it.

As with anything paintball, your mileage will vary. I guess my previous post where toward a worse case/hammering paint into the barrel like the OP's post.

I personally underbore about a sizer down from whatever match would be. I'd use a .680 insert on paint that is roughly at the .682-.684. Most of the time, I would have no issues, but once in a blue moon you'll get that one paintball that is the bad apple of the batch and it gets hammered into the barrel and goes nowhere.... or if it makes it out of the barrel in my experiences, it hasn't been too straight of a flight path.

I also had a handful of instances in which brittle paint would swell a bit and it won't enter the sizer/back and goes kasploosh in the breech.

[Castro #66]

So the answer is "Probably not". What brand of paint is it? Most lower-grade paintballs are stiffer and therefore less flexible when pushed into the barrel.

[Pdubs]

if you're playing pump, inspect your rounds before hand to insure that there aren't any dimples or abnormalities. Just put those aside and use them for when you play semi or electro.

[hondaxr88]

What bore? and what paint? I feel like the consistency of the paint is the biggest determining factor as to how much you can underbore. Really, you are underboring too much if you are getting breaks as a result.

And it doesnt take THAT much to start having barrel breaks with brittle/tourney paint. The evil I shoot passes a blow through test for about a .683-.684 diameter, and shoots great through my .679 insert, but will start blowing itself up once I drop from .679 to my .677 insert. Not exactly a .020 difference claimed above.

Also, type of breech makes a difference. With the breech on the phantom, I feel like I can't underbore nearly as much because the ball actually sits right on the edge of being fully loaded into the barrel when the bolt is all the way forward(as opposed to the cocker, which actually loads the ball all the way into the insert with the bolt). This makes it a little more violent to significantly underbore than 'cocker based pump, as the ball has to go through compression into the barrel while being fired instead of during the pump stroke (which, unless you are being super violent, should be significantly more gentle).

[bracer028]

Originally Posted by Castro #66

So the answer is "Probably not". What brand of paint is it? Most lower-grade paintballs are stiffer and therefore less flexible when pushed into the barrel.

Evils.

[Castro #66]

Tough call, then. Every once in a while I have the same issue with various brands, but it's usually 1 in over 2000 balls.