Stern defense has the best customer servise! - Stern Defense MAG-AD9 AR-15 Glock 9mm/.40 Magazine Conversion Adapter

Purchase this adapter for my AR 9 build. Had issues with jamming if I put more than 3 rounds( didn't matter if flat or round nose) in the mag. Re-installed the adapter three times and had the same result every time. Called Stern Defense left message and though well that was a waste of time, but to my surprise with in 15 minutes had a return call from Stern. The tech ask me a few questions and then ask me to send some pictures of my upper from inside and outside, also needed to include pictures of lower with adapter installed. The tech said they would call me back in an hour or so, I agreed.

I looked inside of the upper and saw some brass marking on the feed ramp and said dam, took the barrel off the upper, got my hand grander opened up the feed ramp, reinstalled the barrel loaded 17 rounds in the mag, fired 1,2,3,4, to 17 with no issues.

Went back into my house and found a message for Stern Defense telling me to take a look at the feed ramp. Called them and said yes I saw the same thing and fixed the issue.

I have now shoot over 1000 rounds with no issues.

Stern Defense is the way to going if you can't afford a 9MM lower.