Consistent Feed Issue
I'd done some tweaking to my CMMG-lower/FM9-upper Colt-pattern build. Finally got it running consistently .. EXCEPT it would misfeed with two rounds remaining. They were preban stick mags with the mag catch cut, and all three would do the same thing.
With two rounds remaining, one would feed and one would half eject. Tried with ten rounds in the mag, four rounds in, six rounds in ... always did the same thing with two rounds left.
Any suggestions? Mag lips? New springs? Feed ramp?