The CAR816 A2 is chambered in 5.56x45mm NATO. The short-stroke push rod gas piston design is controlled by a three-position gas valve. It’s manufactured with the best materials such as a Carpenter 158 bolt housed in an anti-tilt carrier, 4150 CMV barrel and aircraft-grade aluminum. These materials, when partnered with our unique barrel extension and chamber design, give exceptional accuracy as well as the ability to surpass NATO testing protocols, including destructive testing. Proudly manufactured in the United States.