The video seems to be, shall we say, somewhat biased. If you need a suppressor, bipod, flashlight, and 30x scope on an M14, you also need them on an AR-10 (or AR-15). So the weight difference is really around .5 lb, not the 5-6 lbs between a bare ass AR-15 and a ridiculously loaded up M1A. You gotta compare apples to apples. Compare a like equipped AR-10 to the M14, and the difference becomes much smaller (negligible IMO). The real issue is - what cartridge do you need to get the job done? Are you shooting 120 lb people, 200 lb people, prairie dogs, antelope, bear, elk? It's why there's more than one type of hammer at any hardware store. Different tools for different jobs. BTW, I didn't meet many recruits who would want to shoot a 7.5 lb.308 (or 6.5) more than 5-10 times a day. If you're flinching every time it goes pop, how effective is the weapon?