Quote Originally Posted by T2C View Post
I don't. Carbon deposited on exposed threads after firing 35 rounds is negligible. I shoot the rifle before attaching a flash hider, then compare groups to those fired after the flash hider is installed. It's something I started doing after I saw tight groups at 300 yards with a post ban match barrel sans flash hider back in the 1990's. 10 shots per group is my standard. I shoot 5 warm up rounds, then 3 separate 10 shot groups with a warm barrel at 300 yards. The average group size is entered in my rifle log and the process with flash hider attached gets repeated every 2,500 rounds on a match rifle.

When attaching a flash hider to a match barrel, I apply blue Loctite and screw the flash hider on finger tight. If consistent sub 3/4 MOA groups are not necessary, I attach the flash hider using a peel washer and torque to 10 Ft. Lbs. A witness mark is scribed on the flash hider underneath the barrel and it gets checked frequently.

John Holliger sells good barrels. Yours should shoot.
Thanks.