EXAMINE THIS REPORT ON COLT M16A1 FOR SALE

The M16A2 buttstock is about 5/8" of an inch more time then the earlier versions.  Due to the improved duration it employed a longer buttstock screw plus a spacer.  The swivel is mounted closer to the buttplate. This buttstock is now made use of around the M16A4:    The "C" on the barrel would point out a chrome chamber only barrel. But AFAIK,