Guntec AR9 Carbine Buffer Features The Guntec USA AR9 9mm Carbine Buffer is built from a stainless steel body weighing 8.2 ounces a weight specifically selected to work with the blowback operating system common to 9mm AR pattern carbines rather than the gas impingement system found on 5.56 rifles. Getting buffer weight correct in a 9mm blowback build is critical to reliable function since too light a buffer can cause excessive bolt velocity and premature wear while too heavy a buffer can cause short stroking and failures to feed. At 4 inches in length this buffer is sized to work properly within a standard mil-spec carbine receiver extension ensuring correct travel distance during each cycle. The stainless steel construction resists corrosion and wear from the repeated high speed cycling that a 9mm blowback system produces. A clear polyurethane bumper caps the rear of the buffer cushioning the impact against the back of the buffer tube on every cycle and reducing the harsh mechanical shock that can accelerate wear on both the buffer and the receiver extension itself. That cushioning also contributes to a smoother less jarring recoil impulse compared to a buffer without a bumper. Designed to work with mil-spec receiver extensions this buffer drops into most standard AR9 builds without requiring a proprietary buffer tube. For anyone building or tuning an AR9 carbine this correctly weighted buffer is a key component for dependable blowback function. Guntec AR9 Carbine Buffer Specifications Manufacturer: GunTec Model: AR9 Carbine Buffer Material: Stainless Steel Length: 4 Weight: 8.2 oz Compatible Hosts: Mil-Spec AR9 Receiver Extension Country of Origin: Made in the USA Available At: GrabAGun