The LMT 308 Bolt Assembly is designed with enhanced features like a beefed up extractor proprietary coating that is extremely corrosion resistant, lubricious, and easy to clean. A unique single piece gas ring regulates the correct pressures needed to unlock the bolt resulting in safe and reliable function. Combined with other Lewis Machine & Tool .308 bolt parts and you will have a reliable and durable AR-10.Lewis Machine and Tool Company has been providing US Military, law enforcement, and government agencies with high-quality weapon systems since 1980. LMT is dedicated to providing that same level of precision engineering to civilians as well and is even expanding into foreign military services as well. All LMT Defense products are 100% made in America and they are a qualified 2005 GSA supplier. Lewis Machine & Tool has also won many awards for their quality engineering and excellence in business