An end plate sling adapter is a replacement end plate that adds an integrated sling attachment point at the rear of the receiver. Installed between the lower receiver and the castle nut, it provides a QD socket or loop for single point (and some two point) slings. Works with AR-15/AR-10 lower receivers, mil-spec or commercial carbine buffer tubes (receiver extensions), castle nuts, buffer/spring assemblies, and collapsible stocks. Compatible with QD sling swivels or hook-type hardware; ambidextrous versions support left/right use.