THE GREATEST GUIDE TO COLT M16A1 FOR SALE

The M16A2 buttstock is about 5/8" of the inch for a longer period then the earlier models.  Due to greater length it employed an extended buttstock screw along with a spacer.  The swivel is mounted nearer for the buttplate. This buttstock is presently used within the M16A4:    The "C" to the barrel would indicate a chrome chamber only barrel. B