We are now fully stocked with AR-15 barrel nut shim sets. They work with all AR-15 barrels, including 223, 5.56, 6.8 SPC and 300 BLK. Our shims guarantee you perfect and hassle-free barrel nut / gas tube alignment within the correct torque specs every time. The best 5$ you will ever spend! Check ’em out HERE along with our instructional video.