Shop › FAXON DUTY BBL 556NATO 20" GNNR BLK FAXON DUTY BBL 556NATO 20" GNNR BLK $188.60 Faxon Firearms Duty Series, Gunner, 1:8 Twist Barrel, 556NATO, 20", Rifle Length Gas System, Fits AR-15, Nitride Finish, Black 15A58R20NGQ Quantity: Add To Cart Added! Faxon Firearms Duty Series, Gunner, 1:8 Twist Barrel, 556NATO, 20", Rifle Length Gas System, Fits AR-15, Nitride Finish, Black 15A58R20NGQ