Anyone have experience with magazines from "A.S.C. New Britain CT?" I have a couple for my 9mm AR-15. They don't seem to feed reliably/at all depending on ammo.
It's a LAR multi-caliber lower and CMMG 9mm upper. I don't remember who made the mag well adapter.No experience with those, only the 5.56/.223 version and no problem.
I'm going to ask your "brand" of AR, if it's not a Colt, it could be a little more understandable. Since there are so many different versions of magazine adapters, the specifications they worked off of, to build their magazines, may cause reliability issues, due to tolerance stacking. And besides, I have no idea if they used a Colt as their pattern!
I would contact the manufacturer of your lower / magazine adapter, and see which brands they recommend, and go from there!