The advanced SureFire SFMB-338 5/8 x 24 muzzle brake, which fits 8.60 mm (.338 caliber) rifles with 5/8 x 24 muzzle threads, greatly reduces both recoil impulse and muzzle rise and features neutral porting. Its patented Impulse Diffusion design minimizes side blast and rear-directed concussion effects. The SFMB-338 5/8 x 24 also serves as a rock-solid mounting adapter for .338 caliber SureFire SOCOM Series Fast-Attach suppressors. Precision machined from US mill-certified heat-treated stainless steel bar stock-including high-precision single-point cut threads for optimum thread interface-the SFMB-338 5/8 x 24 muzzle brake is given a black Ion bond DLC coating. When used in conjunction with a SOCOM Series suppressor, the patent-pending design of the SFMB-338 5/8 x 24 provides multiple bearing surfaces to ensure superior suppressor alignment. A rear labyrinth seal minimizes potential carbon build-up in the indexing system and facilitates suppressor removal after extended firing. All SureFire SOCOM Series muzzle brakes have blind pilot holes at the 3 and 9 O'clock position to enable fine-tuning of recoil characteristics for individual shooting styles or ammunition characteristics. They also have blind pilot holes at the 6 O'clock position to enable indexing the adapter at bottom dead center, and to pin-and-weld on short-barreled rifles. SureFire muzzle brakes are individually inspected for concentricity and alignment, and each is covered by SureFire's No-Hassle Guarantee. Features: Black ion bond DLC coating Installation requires no permanent modification Made from heat treated stainless steel bar stock