Surefire PROCOMP Muzzle Brake, 556NATO, 1/2 x 28 RH, Black Finish PROCOMP-556-1/2-28 The advanced SureFire ProComp 556 muzzle brake" which fits M4/M16 weapons and variants with 1/2-28 muzzle threads" greatly reduces both recoil impulse and muzzle rise so that the weapon tracks straight back 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 556 duplicates the design of the SureFire SOCOM SFMB-556-1/2-28 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 556 muzzle brake has a black Melonite finish that provides maximum protection under harsh environmental conditions. The SureFire ProComp 556 muzzle brake has a blind pilot hole at the 9 o'clock position to enable fine-tuning of recoil characteristics for individual shooting styles or ammunition characteristics. Each ProComp 556 muzzle brake is covered by SureFire's No-Hassle Promise.