AR: M16, TAR-21, L85**, SCAR-L
LMG: You'll accept the M60, but not the Stoner?
Personally, I'd worry more about requiring coms before I worried about what weapon you carry. If it is a mag compatibility issue, then I'd see the logic, but who cares if somebody is using a m16 rather than a 417 like he should be???
I'm building a custom gun, AR platform, M4 mags, but is nothing that was ever issued, or ever will be issued. So that would be unacceptable?