Now you can add sling swivels to your favourite pump action shotgun without altering it. Uncle Mike's Magazine Cap Swivel Sets have a factory style magazine cap with the quick detach swivel base included. Just unscrew the factory magazine cap and replace it with the new cap. For the buttstock, a 3/4" wood screw swivel base is included, along with two 1" Super Swivels. 12 gauge only.