The Uncle Mike's QD115 Machine Screw Type Swivels designed to replaces many factory non-detachable swivels. QD 115 Swivels from Uncle Mike's have machine screw fore end base and wood screw rear base. These UM Swivels are mounted on pistols, rifles, shotguns and muzzleloaders. Has machine screw fore end base and wood screw rear base Replaces many factory non-detachable swivels Mounted on pistols, rifles, shotguns and muzzle loaders