Brownells BRN AR-15/M16 5.56MM BOLT CARRIER GROUP, MPI, NITRIDE AZT-M4-556-ST-004

The Brownells Bolt Carrier Group is made by a well-established firearms industry manufacturer, made to our specifications.  All components of the BCG are made in-house, under one roof, not outsourced to the lowest bidder.  Even the firing pin and gas key, commonly outsourced components, are machined by our manufacturer.  These Bolt Carrier Groups are rigorously inspected at the factory, for hardness requirements, fitment, cam path geometry, magnetic particle inspection of the bolt and more.  Materials for these Bolt Carrier Groups are certified in batches and the dimensions are true to the most current military specifications.  Proudly Made in the USA.

• Bolt is made from 9310 hardened steel, shot peened and magnetic particle inspected
• Carrier is machined from 8620 hardened steel
• Extractor is machined  from 4340 steel and includes mil-spec extractor spring and black o-ring
• Gas Key is machined from 4130 steel and attached with Grade 8 screws, that are properly staked into a milled “valley” to ensure proper positioning
• Cam Pin is machined from hardened 4340 steel
• Firing Pin is made from 8740 steel, center-less ground and hard chrome coated
• Magnetic-particle inspected Bolt
• Extractor includes spring and rubber insert
• Includes torqued and staked gas key
• Functions with any cartridge based on the 5.56 NATO cartridge case

The Brownells M16 5.56 Complete Bolt Carrier Group is designed to work easily and reliably in any AR-15 or M16 rifle chambered in 5.56x45mm, 300 AAC Blackout or .223 Remington.  The Brownells M16 5.56 Complete Bolt Carrier Group comes with a bolt, bolt carrier, gas key, firing pin, cam pin and a firing pin retaining pin.