Factory New at Emmett Gun Store in Emmett, ID. The latest update from HK-USA to the commercial variant of the legendary HK416, the MR556 A4 represents an enhanced example of “no compromise” HK performance. Chambered in 5.56 x 45mm, its short-stroke gas piston operating system does not impart hot carbon fouling back into the action, allowing the weapon to run longer, with less maintenance and with less wear on internal components than direct-impingement ARs. Its adjustable gas regulator allows the operator to tune the action specifically for suppressed or unsuppressed operation. Fully ambidextrous controls, lighter weight and a slimmer profile make the new A4 easier to operate, manipulate and employ. For those who demand an AR with unmatched capability and uncompromising reliability and durability, the MR A4s remain the top tier solution. Specifications Length Collapsed: 33.25″ Length Extended: 36.5″ Weight: 7 lbs 10.72oz Caliber: 5.56mm Color: Black Lower Receiver: Forged, HK Ambidextrous Upper Receiver: Forged, HK MR556A4 BCG: MR556A4 Rail: MLOK Trigger: HK Two-Stage Barrel: 16.25″ Cold Hammer-Forged Barrel, 1:7 Twist Gas System: Short-Stroke Gas Piston Gas Block: Adjustable Charging Handle: HK Ambidextrous Muzzle Device: Birdcage Lower Parts Kit: Ambidextrous Buffer Tube: 6 Position Buffer Assembly: HK Heavy Buffer Stock: Slimline HK416 Stock Grip: HK