This is my first stripped lower assembly and I've hit a snag. I'm guessing with the threaded bolt catch pin, i'm supposed to back it out with a hex wrench. Aero says 1/16th on their site. My problem is that it feels like the pin is stripped when I try and place the wrench in it and start turning. Any advice?

Do you have any others that fit better?  Maybe try metric?  I've put together a couple M4E1 lower.  I never had an issue with that pin.  I just found an allen wrench that fit and away we went.

I'm an idiot. I was turning it incorrectly. It's kind of an awkward angle to work at, but I just got it. Thanks.