Ideal for attaching 5/8-24 muzzle brakes, suppressors, or any other alignment critical devices to your AR-15/M16 barrel. Both Internal and external threads are single point cut in same operation to tight UNEF Class-3 tolerances for perfect concentricity and alignment. Compact design moves muzzle device only .100” forward maintaining full thread joint strength. Precision CNC machined from pre-hardened HTSR 400 series stainless steel bar for superior heat and corrosion resistance. Available in an advanced PVD (Physical Vapor Deposition) matte-black finish, offering exceptional durability and corrosion resistance at high temperatures, making it ideal for full auto fire as well as suppressor applications. Also available in a matte stainless finish.
Big Book Catalog, Issue:67, Page:176
HTSR 416 stainless steel, HRC 26-32, PVD matte black finish - or - matte stainless finish. .625" long, .825" OD, .750" wrench flats.