Shop › DBB BBL 556 16" CARB MED 1/9 BLK DBB BBL 556 16" CARB MED 1/9 BLK $86.00 Diamondback Barrels Medium Profile Barrel, 556NATO, 16" Barrel, 1:9 Twist, Carbine Length Gas System, Nitride Finish, Black 556C16M50B9 Quantity: Add To Cart Added! Diamondback Barrels Medium Profile Barrel, 556NATO, 16" Barrel, 1:9 Twist, Carbine Length Gas System, Nitride Finish, Black 556C16M50B9