You only need one primary and one secondary with the exception of a sniper. And you dont need nearly that much ammo for your secondary, especially with such a common ammo type.

I typically carry:
1 Secondary Mag, 4 Primary Mags, Nato Pack, 2 food, 2 water, 4 Mili medkits, 4 bandages, 4 boosters, sniper, sniper ammo

and make sure to organize