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

Was: $120.00
Now: $89.99
(19 reviews) Write a Review
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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. This BCG has the full-auto profile, but it will also perform perfectly in your semi-auto builds, and even in a full-auto build if you are lucky enough to have that opportunity.


  • 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: 4140 Billet Gas Key with Grade 8 Hardened Fasteners, Staked per MilSpec
  • Bolt is Magnetic Particle Inspected (MPI)
  • Fastened with Grade 8 screws
  • Staked Per Mil-Spec
  • Firing pin machined from 17-4 H-900 Stainless Steel
  • Retaining pin 
  • Cam pin also 4140 with Nitride Finish
  • All Parts Made in the USA

19 Reviews Hide Reviews Show Reviews

  • 4

    Posted by Edward on Jul 1st 2022

    Excellent finish and fits perfect inside the upper. It's was on sale so I thought give it try out after some of the earlier reviews. It's a good buy.

  • 5
    Amazing for the price

    Posted by Michael B on Apr 2nd 2022

    This bcg has had absolutely no trouble with over a thousand rounds from a 16" ar. Only part I can see needing to be replaced is the cam pin which exhibited a bit of wear, and the extractor spring which was not particularly strong. Other than that, you should have zero issues.

  • 5
    Excellent BCG!

    Posted by Mark Stafford on Mar 5th 2022

    I purchased an inexpensive AR-15 and wanted to upgrade the BCG. This fits the bill perfectly.

  • 4
    Bolt carrier assembly m 16

    Posted by Tito Dirosato iii on Mar 1st 2022

    Looks to be up to mil specs. Bought in case one of mine fails. Breek arms has fast shipping and good prices.

  • 5

    Posted by Robert S King on Feb 21st 2022

    As always these guts have the best AR parts. I purchased a 5.56 BCG. I expected it to be nice but it's top quality parts and coating.

  • 5
    Auto BCG

    Posted by Ron on Jan 21st 2022

    Shipping was fast. BCG is well made and certainly appears to be a quality item