5.56/300 Blackout Nitride MPI Full-Auto Bolt Carrier Group

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Breek Arms is dedicated to using the right components for the most reliable functioning AR builds. The most important part in your AR15 is the bolt carrier group. This is why we’ve found a superior BCG with a high quality low friction nitride coating that protects against corrosion and heat that an AR15 endures over time. Each bolt carrier group under goes a magnetic particle inspection (MPI) to ensure you get a simple, no frill BCG that provides you with the reliability and performance you expect from a high end AR15.


  • New AR15 Bolt Carrier Group
  • Fully Assembled Bolt & Carrier Assembly
  • Caliber: .223/5.56 & 300AAC/Blackout
  • Carrier Steel: 8620
  • Carrier Finish: Nitride
  • Bolt Finish: Nitride
  • Bolt Steel: 9310
  • Profile: Full Auto Profile
  • Gas Key: Grade 8 Hardened Fasteners, Staked per MilSpec
  • Bolt is Magnetic Particle Inspected (MPI)
  • Gas Key Hardened to USGI Specifications
  • Fastened with Grade 8 screws
  • Staked Per Mil-Spec
  • Firing pin
  • Retaining pin 
  • Cam pin
  • All Parts Made in the USA
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