Surefire muzzle brake beveled shim

[n4p226r]

Anyone know what happens if you don't use it? I recently had 2 socom muzzle brakes installed and pinned on 14.5" barrels. The dealer said they install as per surefire's directions. Obviously the beveled spacer wasn't used or I wouldn't be here asking. I sat on Hold waiting for Surefire to pick up the phone for 10 minutes then 12 minutes then 45 minutes with no answer. Maybe they had a long weekend as this was Friday.

Thanks
Bill