I installed this on an Aero Precision Lower with an Anderson LPK. It fit good but the set screws would walk unless really torqued down. The biggest issue I had was when the bolt cycled it would release the magazine. I pulled the unit out of the Aero Precision and put it in a Polymer80 lower and it functioned flawlessly. I like the concept but it is a bit finicky and may not function in every lower.