I based my post on what i know.
Some of my mates in the RAF regiment carry:
8 mags in their webbing/assult vest,
1 mag in the weapon - at all times,
4/5 small grenades
maby an extra pack of 200 rds in clips in a cardboard box/fabric sling in their burgen
The anit-armour guys carry 4/5 mags,
4 small grenades,
and their weapon, be it LAW/NLAW
the guys with LSW's carry mainly ammo, as they are the fire support teams and have:
1 LSW
12 mags in webbing
1 mag in weapon
no grenades, maby 1 or 2
1 cardboard box/sling of 200rds in the burgen.
That is what i know, it may be wrong