Colt PreBan AR15A2  SPORTER II Carbine
COLT CAR15A2
Caliber 223
20rd Colt mag
16" Barrel
Condition: Like New
Other:  Collapsible Stock
             Bayonet Lug
             Flash Hider/muzzle break
             Forward Assist

I think the Colt model is R6420

Late preban producdtion AR15A2 transition with A1 rear sights.

Colt CAR15A2 Receiver

KATS Firearms