Utg leapers rear receiver sling adapter - Leapers UTG Model 4/15 Receiver Extension Tube Ambi Sling Adaptor Mount w/ QD Sling Swivel

This is a well made and ingenious part. The fit and finish are very good and a simple oiling of the push button makes it work better. I had bought 2 one for my M&P 1522 and one for my Colt Umarex M 4. It does not fit the 1522, I found out, because the bottom Ridge where the detents for the sliding stock are, continues all the way to the back of the receiver, henceforth making it impossible to install. I suspect the molding helps support the plastic buffer tube and I think I will not grind it down because it might compromise the integrity of the plastic tube. However, the sling adapter fit perfectly on the Colt Umarex, because the metal buffer tube is mil spec, and it works and looks great!!!! And also I don't think there is anything out there that I know of that would fit the 1522 because of the continued bottom ridge. God Bless keith