Our most popular bull barrel .223 Rem. The Bull 20 is the standard for a bull barrel AR rifle. 24" Length .416 Stainless steel bull barrel. 6 grooves, right-hand 1x9 twist, button rifled. Chamber: .223 Remington. Method of Operation: Gas operated rotating bolt. Bolt & Carrier: 8620 steel bolt carrier, heat treated and plated per Mil Spec Phosphated steel bolt, heat treated and plated per Mil Spec. Sights: None (mounting optics only). A3 Flattop, forged 7075-T6 aircraft aluminum alloy. Hard coat anodized per Mil Spec and Teflon coated black. Dust cover. Shell Deflector. Round Forward assist. Right hand ejection. Lower Receiver: Forged 7075-T6 aircraft aluminum alloy. Hard coat anodized per Mil Spec and Teflon coated black. Semi-Auto trigger group. Aluminum trigger guard. Aluminum magazine release button. Stock: Standard A2 Black Zytel Mil Spec w/trap door assembly. Handguards: Aluminum ribbed free float tube. Each rifle comes with 1-30 round magazine. Scope Not Included.