The guardian f5 rifle features an all hm match grade defense barrel.It also features a custom hm defense 10 3/8 inch, free float 1913 picatinny rail that is compatible with the magpul m-lock mounting system.Some other components of the rifle include an m16 bolt carrier group with patented hmb bolt and mil-spec components, including the trigger & fire control group, charging handle and buffer tube/spring.Also a custom trigger guard, cnc machined muzzle brake, and steel gas block.Action: Semi-AutoCaliber: 5.56x45mm NATOBarrel Length: 16"Capacity: 30+1Trigger: Mil-SpecStock Description: Mil-Spec HMMuzzle: Muzzle BrakeReceiver Material: 7075-T6 AluminumSights: Optic ReadyBarrel Description: Chrome Moly SteelTwist: 1:7"Barrel Length Range: 16" to 16.99"Hand: RightStock Finish Group: BlackMetal Finish Group: Blued/Black