This high quality steel AR-15 1/2" x 28 threaded jam nut is for .223 / 5.56mm rifles with .750 outer diamiter. Jam nut is precision CNC machined and made in the USA. The AR-15 1/2" x 28 Thread Jam Nut is designed to be tightened up against your muzzle brake or flash hider for proper indexing. Jame nut has matte Military style black oxide finish 1/2"x28 Thread Pitch.
