for indoors I'll run 5 x 70 round AK mags and at least one pistol with 3-4 mags. when I say at least, I might pack 2 or 3 pistols with a spare mag each or more depending on kit real estate. (this is all Duckmans fault!) why change mags when you can just pack more pistols and grab a different one when you run dry?
for outdoors with the AK rig I'll use those same 5x70 round mags plus 3x150 round mid caps. again, as many pistols and mags as I can find space for.
with an M4, I run what I can carry as I hate walking back to the safe zone to reload. 9x130 rd midcaps, 1x160 rd midcap, and 2x180 rd midcaps.
8 of the 130's go in my rig and one in the gun. the other 3 higher midcaps go on a drop leg mag carrier. pistol mags, as many as you can find space for and physically carry.
but it totally depends on the game. some games allow unlimited pistol mags while having an AEG ammo limit. less primary mags means more space for pistols and mags! :P
all mags are metal!