These are unfinished Muzzle Brakes, minus the barrel thread, this allows you to get threaded to any thread you desire, we would recommend as larger as you have the option, but you and your gunsmiths choice.
5 port brake suited for larger magnum calibers, Custom designed to help keep muzzle blast from the ground when shooting in prone dry conditions. These Brakes are made from 4140 steel
The weight is 675 gm (23.77oz).
