The 45° Muzzle/Cylinder Chamfering Cutter & Steel Pilot by Brownells is designed to chamfer the edges of rifling and revolver cylinder chamber mouths for improved bullet exit and faster reloads.
It includes a cutter, handle, and one pilot, suitable for .45 ACP calibers, with additional pilots available for various other calibers.
The set is contained in a polypropylene box, with the main cutter being 5/8" in diameter for larger barrels and cylinders, while other sets have a ½" cutter.