The receiver mounting scheme of our sling and hook loops for the Mossberg 500/590/835 substitutes custom-machined Chicago fasteners for the trigger pin. The sling or hook loop is free to rotate about the retainer. A rubber gasket keeps the sling loop from marring the receiver finish. Sling mounts are finished with mil-spec manganese phosphate. All our receiver mount sling attaching solutions are fully compatible with our four-shot and six shot receiver mount SureShell shotshell carriers (but not the eight-shot versions).