Bugger - I was going to ask how he was going to carry 800rds of 7.62mm plus a GPMG along with all the rest of his kit and body armour.
By carrying it.
My service GPMG was the M60E3... I generally humped it with the light barrel fitted and a single heavy barrel (and glove) stowed in my barrel bag.
I think we already know the answer to this one is "yes", but dare I ask whether you were carrying your M60E3 before the days of plate body armour on general issue? And if not, what was the weight of your body armour, helmet, and water?
What's your opinion of the statement from the official training pamphlets (presumably USMC)? "The M60E3 (light weight version of the parent M60) was fielded with the intention to reduce the load carried by the gunner. However, the reduction in weight resulted in firing limitations and a loss of reliability that severely restricts the use of the weapon in the Fleet Marine Force. Consequently, troop acceptance of the E3 has been very poor. This gun will be replaced by the M240G."
Being required to change the barrel every 100rds makes that light barrel look like a false economy... "However, the light weight barrel is not safe for overhead fire and is not capable of sustaining a rapid rate of fire of 200 rounds per minute without catastrophic failure of the barrel".
I'm just curious as to why you think that carrying an 8.5kg gun, a 3.5kg spare barrel, and 21kg of 7.62 is a Really Good Idea when your personal equipment already weighs a minimum of 15kg. Because 50kg isn't exactly something you're going to be doing fire & manoeuvre with, unless you either a) wear bright red underwear outside of your blue uniform, or b) are prone to exaggeration...