Right now it's difficult since there is no scientific data really. Except what's been done by mfgs and I don't trust that. Flasc says. 687 lapco says. 683 etc etc
If you have lots of money get 2 f1 shooting chronys andI all tthe barrels and pickup wwhere punkworks left off
It has to be slightly tighter than the round for the rifling to engage. That's if you go that route. And that's if hammerhead rifle pattern even works as good or better than lapco. They may be the same I dunno
Lapco claims they did various testing with different twist ratios, barrel lengths, groove types/sizes and bore sizes. The resulting 2 barrels they offer are supposedly the best you can get. They made those barrels for tiberius for use on the t9 though so results I'm sure will vary depending on your platform. We already know the t9 internal reg has problems WWhen combined with a rifled barrel.
Last edited by Keebler; 12-11-2012 at 12:09 PM.