The M16A2 buttstock is about 5/eight" of an inch for a longer period then the earlier products. As a result of increased duration it utilised a longer buttstock screw plus a spacer. The swivel is mounted closer into the buttplate. This buttstock is at this time employed within the M16A4: https://paxtongihfd.blgwiki.com/1077252/the_basic_principles_of_colt_combat_elite_commander_45_acp