If it's an ammo limited game...I'll spread the rounds out evenly between the mags that best fit the rig I'm wearing to the game. I'll sometimes load one hold-out mag with a bit more.
I've only got 9 mags for my FAL...but find I only use 6-7 of them regularly.
12 mags for my M4...but 2 are usually accessible to teammates so they can grab one if they run dry.
I run 2-3 mags in CQB...the skirmishes rarely last longer than a mag...maybe two. Drop leg, weak side seems to work well for that.
3-4 pistol mags...2 would probably be enough...but pistols are sooooo much fun.
In short, think about what you're getting into...what type of game and who the other people are...load out accordingly. Then take one extra, just in case.
