I think an AR-10 with gas piston would make most of these folks happy. I’ve shot this weapon and liken it to driving a Porshe after getting out of a Camaro...no comparing an AR-10 to M-4/M-16. More range, knockdown power and cleaner firing with no gas being used to operate the bolt. Can’t say anything about battle conditions but no weapon is perfect. Would you rather carry an inaccurate AK that shoots with mud on it or take care of your weapon and be able to protect yourself out to 600 yds? And since that is how far we need to carry the fight to the enemy now it makes perfect sense to field both weapons...AR-10’s in Afghanistan and M-4’s (in 6.8) in urban conflicts.
I've yet to see or hear of one.........