The M16A2 Buttstock is about five/8" of an inch longer then the sooner designs. Because of the enhanced size it used an extended buttstock screw in addition to a spacer. The swivel is mounted closer to your buttplate. This buttstock is at the moment utilised within the M16A4: And since https://devinkkigd.wikitelevisions.com/6847216/colt_m16a1_for_sale_things_to_know_before_you_buy