The M16A2 Buttstock is about five/8" of the inch for a longer period then the sooner versions. Because of the enhanced length it applied an extended buttstock screw along with a spacer. The swivel is mounted nearer to your buttplate. This buttstock is at the moment used over the M16A4: https://socialclubfm.com/story8971324/the-greatest-guide-to-colt-m16a1-for-sale