Accuracy fixed.

[Dave_H]

Dave, I would suggest having a profession to check it if worried. If I spent that kind of money on an upper I'd likely bed it and go have some fun and see what it would do or have a machinist inspect it and do it with the proper equipment if needed.

I'm probably going to do just that...bed the barrel extension and the gas block and try it. I have a couple of barrels (a Ballistic Advantage 18" SPR profile with rifle gas, and I just bought a Lilja 319 from another forum member) to try. Hopefully one of them will shoot well enough to not worry about lapping the upper.

I built a rifle (5.56) for my son for his birthday in April. I used a good barrel from a very well known manufacturer. We can't get it to shoot for s--t. It functions flawlessly, but is all over the place as far as accuracy. I'm really disappointed in it and my son has no confidence in it which kills me. We're going to pull the upper back apart and lap it and bed the barrel and gas block and try again. The barrel-to-upper fit was tight (I couldn't fit a .001" shim between them.), but I didn't lap the receiver or bed the barrel. I think I'm going to increase the barrel nut torque a few ft/lbs. also. I hope my results are as good as the OP's.