RUGER New and Old Model Blackhawk Super Blackhawk and Bisley Model No Drill Scope Mount This mount fits on any length barrel PLEASE NOTE: Not compatible with the .45 Colt Caliber or 30 Carbine This scope mount does not fit Flat Top model RUGER This scope mount does not fit Hunter Model RUGER or 357 Maximum A no drill and tap scope mount for the RUGER Blackhawk and Super Blackhawk that you can depend on. The rugged two piece construction makes installation a breeze. A billet Aluminum underlug is secured with two Brass set screws to reduce any marring of your barrel surface. Tightening the Allen screws secures the underlug to the barrel Mfg: Weigand Combat