Tiger Rock AR-10 .308 6" Aluminum Blank Muzzle Brake for 5/8"x24 Pitch -Silver Silver. 308 chambered in .308 has a 5/8"x24 thread pitch. It is an aggressively styled blank that functions much better than a threaded muzzle device as it functions to reduce overall felt recoil. The straight design gives the shooter a more pronounced "twang" noise effect (the sound created by the tongue of the brake pressing against the side of the barrel) and works to push any muzzle blast or sound forward and away from the shooter and bystanders. The front face of the brake has reliefs cut into the slot to allow light to pass through to the shooter's eye rather than deep v-cuts which create an unnatural twitch in the sound wave. This product is pre-packaged in retail packaging. Package Contents: Tiger Rock AR-10 .308 6" Aluminum Blank Muzzle Brake for 5/8"x24 Pitch Tiger Rock MBR308S: AR-10 .308 6" Aluminum Blank Muzzle Brake for 5/8"x24 Pitch -Silver Silver