Had a Colt slick side upper laying around and couldn’t find an A1 stock and a slick side bcg for love nor money so I decided I needed and AR9. after researching magazine conversion inserts it looked like one that was definitely good cost about twice as much as one that may or may not work so I started there, and got a Stern Defense for Glock magazines. It has a last round bolt hold open. More about this later. why Glock vs Colt magazines? Availability, reliability, and cost.
