Thus, LMGs (aka squad automatic weapons in some circles) and heavier general-purpose machine guns are generally designed so that the barrel can be quickly and easily swapped for a spare, allowing the first one to cool down while the gunner keeps shooting.
That’s not ideal, though, as steel gunbarrels – especially ones intended to stand up to sustained automatic fire – are heavy. Furthermore, even though barrel change is quick and simple it means an inevitable pause in the suppressive fire which is keeping the enemy’s heads down and allowing the gunner’s team-mates to manoeuvre and win the fight (that’s the theory, anyway).
Excellent!! Already the Army is looking at an M240 with the receiver made of titanium to reduce weight.
Of course, all this comes at a much greater cost per weapon, but let’s face it, this is pretty small potatoes on the procurement