The Tierney Arms Company Ghille Muzzle Brake was designed using the latest state of the art C.A.D. software along with real world testing to ensure maximum recoil reduction. It features high efficiency variable geometry porting that is biased to rear and slightly up, minimizing felt recoil and muzzle climb. It is manufactured with a proprietary process we created that enables us to machine a precision brake with a matching lock nut, that when assembled (on a properly threaded barrel) creates a "seamless" fit that you can DIY. All that out of a compact/lightweight brake that won't change your barrel harmonics or shift your point of impact.