I am having a slight issue with the current LR308 build with my duramag ss 20rd magazine not locking when the BCG is in battery. Im trying to eliminate if its either a magazine, bcg or receiver sets that could be put of spec. Willing to drive to you or meet up etc to just quickly swap bcg just to test and eliminate the current issue. If you look at the pictures, the duramag gets narrow towards the front end of the feed lips thus causing the bind on the aero NIB bcg and not moving forward into battery. Also the empty mag wont lock in with the bcg in full battery as well.

do you have multiple of the duramags to measure if there is variance between them? Way for north, but can measure my duramag feed lips width.

Try another brand of magazine. Take the upper off and insert a empty mag. Does the bolt catch lift all the way up or rub on the side of the mag? Build spec?

Yeah i have multiple, but I figured out that its the duramag that is the issue. I purchased a pmag to try out on the rifle and it works without any issue. The pmag has a wider feed lip width and it actually widens out toward the front as well. So im going to try and slowly grind off some material on the durmag and see if that will solve the issue.

The duramag was the isue, tried out pmag and it works great without issue. Going to try and widen out the feed lips on the steel mag and see if it will fix the issue.