The hardened steel muzzle crowning tool is designed to cut a precise 11 degree target chamfer on barrels, providing effective rifling protection without excessive depth. The 90 degree - 11 degrww calculation results in a 79 degree angle, which is the basis for the tool's designation. The tool features eight precision-machined flutes that deliver smooth, chatter-free cuts, minimizing the need for additional lapping or stoning. It is equipped with a 1/4-20 thread compatible with Brownells muzzle chamfering handles. For optimal precision, use this tool with our muzzle pilots to ensure accurate alignment with the bore. Available in 1/2 inches diameters, it accommodates most rifle and handgun barrel sizes.