GETTING MY COLT 6721 UPPER FOR SALE TO WORK

Be aware:  The Colt 6940 relatives of rifles are proprietary built, with handful of user serviceable parts.  Precise instruments are required to eliminate the barrel nut and barrel.  The gas program is unique instead of created to get replaced with mil-spec parts. Colt has made a decision to broaden its AR offerings past the immediate-impingeme