The M16A2 Buttstock is about five/eight" of an inch for a longer time then the earlier products. As a result of improved duration it employed an extended buttstock screw and also a spacer. The swivel is mounted closer towards the buttplate. This buttstock is currently used about the M16A4: Up https://coltm16a1forsale33344.amoblog.com/little-known-facts-about-colt-python-6-for-sale-53210479