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.


  • 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


MFG Geissele
MODEL M4A1 5.56 Bolt Carrier Group
TITLE Geissele M4A1 5.56 Bolt Carrier Group

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