Quality USA Manufactured Jam Nuts for your muzzle device installation in select sizes. Perfectly time your muzzle device to your barrel. Reusable and designed to provide higher levels of torque to be applied. Sold as a 2pk.Instructions for certified gunsmith: 1. Thread jam nut against the shoulder of the barrel.2. Thread on muzzle device by hand.3. Using the appropriate tool on both the muzzle device flats and  on the jam nut, countersink both in oppossing direction until desired torque is achieved and muzzle device is properly timed. 4. Boresight to ensure proper alignment.DO NOT OVERTIGHTEN.  Recommended Torque 30-40lbs

2pk Stainless Muzzle Brake Jam Nut