Shop › DD M4A1 UPPER URG 14.5"PB 556 FDE DD M4A1 UPPER URG 14.5"PB 556 FDE $1,450.00 Daniel Defense M4A1 Upper Receiver, 223 Rem/556NATO, 14.5" Barrel (16" OAL with Pinned Brake), Carbine Length Gas System, 1:7 Twist, M4 12.0 Rail, Flat Dark Earth Finish, Fits AR 23-004-13150 Quantity: Add To Cart Added! Daniel Defense M4A1 Upper Receiver, 223 Rem/556NATO, 14.5" Barrel (16" OAL with Pinned Brake), Carbine Length Gas System, 1:7 Twist, M4 12.0 Rail, Flat Dark Earth Finish, Fits AR 23-004-13150