Machined from pre-hardened, stainless steel bar stock. Wrench flats on shoulder make installation and removal for use on multiple devices simple and easy. Compact design moves muzzle device only .100" forward maintaining full thread joint strength. All threads are single point cut in same operation to tight UNEF Class-3 tolerances for perfect concentricity and alignment. Allows attachment of 5/8-24 muzzle devices to a 9/16-24 threaded barrel.
Big Book Catalog, Issue:73, Page:178