This is a Surefire Muzzle Brake known as the PROCOMP chambered in 762NATO, model PROCOMP-762-5/8-24.
The advanced SureFire PROCOMP-762-5/8-24 muzzle brake" which fits AR10/LR308 rifles and variants with 5/8-24 muzzle threads" greatly reduces both recoil impulse and feature neutral porting so brake loads bi-pod legs evenly to keep you on target for faster shot-to-shot recovery. Its patented Impulse Diffusion design minimizes side blast and rear-directed concussion effects. The PROCOMP-762-5/8-24 duplicates the design of the SureFire SOCOM SFMB-762/.308 muzzle brake" but unlike the latter it cannot be used to mount SureFire SOCOM suppressors. Precision machined from US mill-certified steel bar stock-including high-precision cut threads for optimum thread interface-the PROCOMP-762-5/8-24 muzzle brake has a black Melonite finish that provides maximum protection under harsh environmental conditions. The SureFire PROCOMP-762-5/8-24 muzzle brake has a blind pilot hole at the 3 and 9 o'clock position to enable fine-tuning of recoil characteristics for individual shooting styles or ammunition characteristics. It also has 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. All that is required is a basic hand drill and appropriate drill bits.
Features:
Black melonite coating
Installation requires no permanent modification
Made from heat treated stainless steel bar stock