Patriot Ordnance Factory Patriot Ordnance Factory, 223 Triple Port Muzzle Brake, 1/2 x 28 RH, Black Finish 308 Designed by POF this nitride heat treated muzzle brake controls muzzle impulse for ultimate accuracy and an unbelievably soft recoil. Comes complete with a nitride heat treated collar and five (5) strike prongs.