Ultimate Arms Gear 1/2"-28 Right Hand Muzzle Threading Gunsmithing Adjustable High-Speed Steel Round Die 1/2X28 TPI 1/2"-28 Right Hand Round Die is Chamfered on Both Faces. Adjustment is Obtained by a Fine Pitch Screw which Forces the Sides of the Die Apart, or Allows Them to Spring Together. A Must When Threading Custom Barrels or Chasing Threads on Standard Barrels. Use to Make Custom or Clean Up Existing Factory Threads. Custom-Made to Factory Specs. Made of High-Speed Steel. UNF Unifed Fine