SilencerCo Single Port ASR Muzzle Brake, 1/2 x 28 RH, Fits ASR Mounts, 9MM AC2628 This single port muzzle brake is compatible with all SilencerCo ASR Mounts and with multiple thread and caliber options" you can shoot suppressed for any demand. It offers quick and easy one-hand-on" one-hand-off attachment and detachment. The 1-port design effectively reduces felt recoil and muzzle climb. Each ASR muzzle brake comes with a shim set and rocksett for easy application. The ASR mounting system comes standard with the Omega 300" Chimera 300" Saker ASR and Specwar families. It's also compatible with Hybrid 46" Harvester Series" Octane Series" and Omega K Series.