Today I installed one of the Kahntrol bolt on muzzle brakes
per their specifications on my 300 win mag. My rifle is a savage 110 FCP HS Precision with the factory heavy barrel. The first time firing, the brake blew off and landed approx 50 yards down range. After a little searching I found it a bit banged up on the outside and completely unscathed on the inside, so I know it wasn't from contact with the bullet. I spoke to the gentlemen shooting next to me for a few minutes, who turned out to be a gun smith about what happened. He thought the reason why it came off could be attributed to the tapered nature of the barrel. After backing out the screws I installed the brake again, this time adding 5in lbs to the recommended 30in lbs from the manufacturer. The next shot held, however the one after that sent the brake 50 yards down range again. Same story after inspecting the brake with the inner parts untouched and the outside a little more banged up. I know the OP is a bit dated, but I thought anyone contemplating one of these brakes would like to hear about my experience.