Black Trench-Coat answer: If you've modded your guns to L3 Ceramic parts and the like, two longarms and a sidearm, five to ten grenades, and four clips.
Pink Mohawk answer: Forget armor, forget pants! Strap yourself down with a few layers of ammo belts, so that once you're out of ammo, everyone's too busy staring at your pearly ass to fire - should give you about two, three thousand shots with that HMG. Have an Assault Canon strapped to your back, alongside those two Battle Rifles, and about ten heavy Pistols dangling here and there for decoration. Grenades? Another layer of clothing! Fifty should do you, plus a clip or two for that Grenade Launcher you've got strapped to your left leg.
That's for a human. Dwarves can probably manage another SMG or smaller in their beard, (Not even kidding here), but if you're going Mohawk, that beard is probably packing a broken-down HMG. Elves and humans can carry similar loadouts, but the ladies can slip a holdout between their breasts, and anyone trying to look too hard is deserving of a good smack to the face. Orks are larger than humans, but not by enough to significantly change the upper limits.
Trolls? Picture it, omae.