colt 6721. I replaced the 16 heavy barrel to a 14.5 colt heavy barrel. it has a pinned gg&g front sight installed by 2 rivers here in the city and has a gg&g rear sight. knights armament  floater hand guards with panes Rogers stock . lots of extras .
2- colt mags I took the echo trigger kit off and the colt trigger group is installed now and has the factory colt hand guards on now the kinights armament handgaurds are gone