Dang, that's a pain. I feel for y'all in enemy territory.
I have a few 4 round AA mags and a couple 7 round mags. They've always run perfectly. I usually just load a standard Pmag with 10 rounds if I want more. So far even doing that has fed just fine. One of these days I'll try some of the AA 10 round mags specifically for the Beowulf. The caveat being I primarily shoot the FMJ stuff. I haven't tried my solid brass Spitzer ammo in them yet. Been saving that for when the dinosaurs come back.