[volunbeer]

You definitely have more rounds downrange with these than just about anyone I have heard of...... with that said, do you not think an alloy barrel with titanium would be more heat resistant? Especially if they increase surface area?

[Chainmail]

Actually the heavy steel barrel acts as a heat sink: a reservoir for the heat that allows the heat from the burning propellant and the internal friction of the bullet running down the bore to safely build up and be absorbed.

A lighter barrel with more radiating surface can't get rid of the heat fast enough, because of the very high levels of heat energy developed my the M2 and its cartridge. Early in its life, there was a water-cooled .50 which allowed much longer bursts but it was a really heavy pig and not suitable for light vehicles or infantry support.