For 5.56 NATO / .223 Rem

High Pressure Tested

Magnetic Particle Inspected

Chrome lined bore and gas key

Properly staked gas key

Extractor O-Ring and Insert

The bolt carrier group is an important component of any rifle or build, so why would you get something less than the best? The Geissele Automatics M4A1 bolt carrier group is built by a Tier 1 supplier for the Department of Defense and built on the same line as BCGs in use by the military. The full mass M16/M4 style bolt carrier is machined from proper 8620 tool steel with a chrome lined bore and properly staked, chrome lined gas key that will last a lifetime. Cut from Carpenter 158 steel, every single bolt assembly is magnetic particle inspected and high-pressure tested to ensure it is defect free. For optimum function, Geissele is utilizing the latest revision extractor spring, o-ring, and insert to ensure reliable extraction with all types of ammunition.Geissele Automatics manufactures confidence, offering quality triggers and components for the warfighter and competitor. They were established in 2004 with the mission to build the highest quality, reliable triggers for competition and their first trigger, the Hi-Speed National Match trigger, was so popular that they were asked by the Department of Defense to produce a select-fire trigger for the United States Special Operations. Again, it was a success and Geissele decided to bring a semi-automatic version to the civilian market for law enforcement and personal protection.