The M16A2 buttstock is about 5/8" of an inch for a longer period then the sooner products. As a result of improved size it applied a longer buttstock screw as well as a spacer. The swivel is mounted nearer to your buttplate. This buttstock is presently utilised to the M16A4: https://colt-combat-elite-defende01127.popup-blog.com/30631698/not-known-details-about-colt-combat-elite-commander-45-acp