MAZOC Firearms

MacCool

Yeh, I agree, but how could the gas block move if it's pinned? Also, no gunsmith that I know would use a set-screw gas block without dimpling the barrel so that at least the rear set screw is set into the dimple, with both the barrel pin and the set screw in the dimple keeping it from rotating. Usually the Rocksett is just a tiny dab...only enough to keep the set screws from backing out.

The barrels that I use, BCM and Centurion, all come from the factory dimpled for the rear set screw on a gas block. I would never rely on that, even with Rocksett, and I always have the gas block pinned (if I'm not using an FSB) in addition to the Rocksetted set screws.

I hope he didn't mis-drill the dimple (assuming he dimpled it) or pin the gas block off-axis. IOW, install the gas block with the gas hole and barrel port misaligned.