SureFire 7.62mm 5/8-24 TThreated Muzzle Brakes PROCOMP-762-5/8-24. The ProComp 556 fits M4/M16 weapons and variants with 1/2-28 muzzle threads while the SureFire ProComp 762 fits AR10/LR308 rifles and variants with 5/8-24 muzzle threads. Whichever you...