AR-15 223/5.56 reusable jam nut for muzzle brake with a 1/2 x 28 thread, CNC-machined from USA-made steel with a durable black oxide finish. Fits AR .223, 5.56 rifles and pistols with 1/2″x28 threaded barrels. This jam nut is used in place of a crush washer or shim kit to properly align a muzzle brake. It can be threaded onto the barrel before the muzzle device.
