Ah- but the problem with the M-16, the Uzi, the BAR, or ANY magazine fed weapon- sooner or later, the magazine is empty. And you have to stop and switch mags. But with M-60s, 240's, or a MA Duece, if you have a friend to keep adding belts to the end of belts, you can hold down the trigger until the gun (or your checkbook) explodes into FLAMES !!! (pant pant pant pant)
On night shoots, we used to turn M-60 barrels incandescent YELLOW.