Your statement confuses me. I understand, correct me if I'm wrong, that your magazine catches on something during insertion (but) ejects clean. Is that right? Assuming that it is, then the problem is confusing. To eject cleanly, the magwell must be clean and slick.
(I'm thinking out loud here.) So how could the mag catch on the way in, and what could it catch on? I'm probably no more a smith than you say you are. I would sit and put that/those mag/mags in again and again until I could tell how far in is the catch place, then look at that area, maybe stick my long fingers in there and see if I can tell, push something else in there to file, cut or scrape it all clean. The magazine catch is the only thing that sticks in there and the side of the mag presses and drags against it until it's seated and the catch drops into the hole. There shouldn't be anything on the mag that would snag the mag catch on the way in, so I'm going to look at the mags too.
Guys, do I have all this right?
