I traded one of my Tula Bakelite mags for an izmash Bakelite mag. For some reason, it would not insert far enough to lock in. I looked on the back locking lug and nothing looked really off, so I just assumed it was a cunt hair off spec and I could shave it down later.

But today I got 2 polymer Polish Radom mags that have the same problem. Only 3 mags I have in my stash that won't lock in. So I was thinking about shaving away a bit of the rear of my magwell so they will fit and I won't have any such problems in the future, but wonder if it wouldn't be a better idea to shave the mags. I'm attaching a picture of the 3 problem mags next to a Tula Bakelite that works without issue for reference.