The Troy Pro Grade Rifle Sling Adapter allows the addition of a Q.D. swivel attachment by sliding over the existing receiver extension on M4 stocks, without modifying the weapon. The adapter virtually eliminates the chance of castle nut rotation. Constructed of hardened aircraft aluminum with a stainless push down button Q.D. swivel. The Pro Grade Rifle Sling Adapter installs in less than two minutes with no gunsmithing required.