
Honestly, with an M-240/249, it doesn't take 45 minutes to do that. It takes about 25-30 seconds. I've fired one at a group of hardened bowling pins on the range, and it takes about 1/2 a second to turn them into matchsticks. Cinder blocks, unlessed hardened by pouring cement around metal pipes placed inside, fare about the same fate.
How long does it take 3 M-240's to accumulate "thousands" of spent rounds? At a contant rate of cyclic fire: about 30 seconds.and correspondents found thousands of spent rounds at the scene.
These facts aren't in support of the soldiers, but more to make you question the validity of everything you read.