I'm reposting an old quote from an old member here (who I hope is still around

) as it seems relevant to this discussion (although in it's original thread this quote was for something different):
Fal Bowden wrote:
As far as the "light load" of the USCM in the film, I've always approximated it to Russian motorised infantry in Afghanistan at the time (though I doubt this was intentional on the part of Cameron). They were expected to fight no further than 200m from their vehicle, and thus only had 5 magazines (4 in a pouch, 1 in the weapon). A squad of motorised infantry needed no more than 150 rounds per man (225 for RPK gunners) and they would operate within reach of their support vehicles where they could return to reload. They therefore also had no need for carrying their own rations, personal kit and so on - just ammo, first aid kit, waterbottle, cleaning kit.
In the instance of the events of Aliens, they went far beyond the reach of their support vehicles and without proper use of their weapons, they were somewhat doomed. However, had they been using their PRs, I doubt the situation would have necessitated more than 2 mags per person or any kind of specialist equipment. The APC, however, was their lifeblood - it contained all of their supplies.
(In the discussion above- we were determining whether it would have made a difference if the Marines "were" allowed to fire their weapons in the hive. The consensus was that it probably would not have made any difference; they would have fared marginally better at most).
Kevin