Tried everything, and I still chop...

[ViperX]

Normally the o-rings would, but it's possible to have a bolt that was milled incorrectly and has a smaller OD than it should.

Another important thing to mention here and maybe your doing this maybe you are not, but don't empty your hopper completely. I know that is not always easy to remember especially when your engaged in a fire-fight, but shooting your hopper empty will most definately cause the balls in the short stack to be more affected by the blow-by you obviosuly are getting.

Doesn't sound like a paint issue, if it were you would see more breaks inside the barrel than you would in the feedneck.

[dstrohl]

When you say blow by do you mean the same thing as "popcorn effect"? If so, this was eliminated by the Alamo City Bolt...

[rojas209]

i have almost the same set up, i had the same problems i just started using core paint and hpa and it fixed my chopping problems, i think co2 makes problems, i had 0 last time i went and i was on full auto most of the time.