Most infantrymen aren't carrying 7.62 and haven't since 'nam. The 240 is (on paper) crew served so you get to spread that load around several people.
I agree with everything else though.
I agree with everything else though.
Good point. This is a big deal because load carried in your hands or, to a lesser degree, on a shoulder strap is more taxing than load carried on a vest.
sa46 addresses it a little bit above that there are different loadouts depending on how you're operating. It wasn't uncommon to move from one place to another with 100 pounds, then drop gear and patrol with a far smaller loadout.
Then again, sometimes your vehicle breaks down and you're now "man packable", which means you do need to be ready to carry a lot. This is really one of the sticking points for women in the military. It's nice to imagine that a specific job will always have a vehicle, but it is doctrine to be prepared to step into the role of infantryman.
The Army doesn't use the M249 as a crew served weapon (unlike the Marines) so the automatic rifleman on each team usually has 600 rounds of 5.56mm linked ammo to carry around.
I'd be curious to see standard ammo load-out by conflict and country.