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

Was: $120.00
Now: $67.49
(28 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

28 Reviews Hide Reviews Show Reviews

  • 5

    Posted by ben pittman on Jul 30th 2023

    cannot complain standard bolt. sturdy build have not shot out of newly built 300 blackout but should work just as well as other companies bolt.

  • 5
    Breek BCG

    Posted by Howard Martin on Jun 27th 2023

    This is a steal! This has to be the smoothest BCG i’ve ever had. Better than the Tool Craft i had in Ballistic Advantage upper. Reliable and functions flawlessly. Goes great with the Warhammer! The sad thing…i didnt know Breek had BCG’s till I found them by chance. Check out their product line, you wont be disappointed. I see a Breek upper in my future…

  • 5
    Helluva Deal

    Posted by Big Boi on May 23rd 2023

    Haven't shot it yet, but upon visual inspection this appears to be high quality. Nitride coating and machining is nicer than some BCGs that cost $200. MPI. Feels very slick installed in the upper. With 10% discount, paid about $60 for this BCG, which is fantastic.

  • 5
    556 Bolt carrier

    Posted by KBrown on May 19th 2023

    This thing runs great and it arrived pretty quickly ?

  • 5

    Posted by Reynaldo Cruz on May 17th 2023

    Breek arms full auto bcg has ran amazing well in my 300 blackout in problems with the first 300 rds and suspect many more to go... well built nicely priced addition to my Ar

  • 5

    Posted by Chet on May 8th 2023

    Seems like very good quality. Can't wait till shoot it