The Magnum Quick Detach Super Swivels from Uncle Mikes are as solid of a foundation to attach a sling as you can find. These QD Super Swivels are designed to take a beating from shotgun rounds to heavy recoiling rifle rounds, these swivels will hold.
The Magnum Swivel and Stud set is made to work with the majority of pump action and semi automatic shotgun to give you solid mounting points for your sling.