Criterion match grade hybrid 1-11 twist 20" ss barrel - Criterion Barrels AR-10 Rifle Length Gas System Barrel

I got this barrel in .308 Win. cal. and installed with no issues. Found that I could not get the bolt to lock open with any weight buffer or spring. Found out the gas port had only been pilot hole drilled. Sent it back to Criterion and they drilled the proper size gas port and range tested it and shipped it back to me within a week and a half - Wow, good service (They also paid for shipping both ways!). So the barrel works perfectly now. Shoots nice even with the cheap ammo. Match grade bore is silky smooth when you pass a patch down the bore to clean it. Shoots tight groups without any break-in. Could not b e happier.