I beleive the AR platform is being used since soldiers are familiar with it, less new training required. I would love to see .308 caliber battle rifles back. One vet I know told me "don't bring an m16 to a gunfight" He'd seen drugged up insurgents take a burst of 556 and one took 9 9mm rounds from an mp5. The m240 guarding their position never failed to stop a threat
