Quote Originally Posted by Adam Van Camp View Post
Do you have any of the brass that is not loaded? Try chambering a sized brass and see if it goes into battery. I have had to bump the shoulder back a few thousands at a time until the the bolt would go into full battery. Then start seating the bullets and testing for full battery.
Yes, I've tried chambering only brass, it all works just fine.

I went one step further and did a plunk test with a live round separated from the lower, it plunks and falls out perfect. I'm starting to think that this is not a seating depth issue at all, rather it is something with the bolt carrier or feed ramps and how they interlock.