The M16A2 Buttstock is about five/eight" of an inch extended then the earlier designs. As a result of greater size it made use of a longer buttstock screw and a spacer. The swivel is mounted closer towards the buttplate. This buttstock is now used to the M16A4: Whether it is https://rafaelgeiov.birderswiki.com/1041520/top_guidelines_of_gold_cup_trophy_colt_45