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Microbest AR15 5.56 C158 MPI Bolt Carrier Group, Phosphate+

8 reviews Write a Review
MSRP: $157.95
You save $44.96
Microbest AR15 5.56 C158 MPI Bolt Carrier Group, Phosphate+
Microbest AR15 5.56 C158 MPI Bolt Carrier Group, Phosphate+
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5 units
Current Stock:

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Microbest AR15 5.56 C158 MPI Bolt Carrier Group, Phosphate+
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Limited Run w/ OCKS Carrier Key Screws

Microbest is one of the finest manufacturers of mil-spec bolt carrier groups for the military and small arms manufacturers. These are individually High Pressure Tested and then undergo a Magnetic Particle Inspection. We recommend degreasing and lubricating before installation. Ships in OEM packaging.


Phosphate M-16 BCG

Mil Spec Carrier

  • 8620 Tool Steel
  • Full Auto M-16 cut

Mil-Spec Bolt

  • C158 Steel
  • Shot Peened
  • High Pressure Tested (HPT) 
  • Magnetic Particle Inspected (MPI)
  • Sprinco Ejector Spring

Mil Spec Extractor

  • 4140 Steel
  • Sprinco Extractor Spring
  • Black Extractor Insert

Mil Spec Gas Key

  • 4130 Steel
  • OCKS Hardware provided by Michiguns
  • Properly Staked
  • Mil-Spec Opening Verified and Optimum Alignment Checked

Weight: 11.6oz

Customer Reviews

8 reviews

  • 5

    Super well engineered and machined BCG

    Posted by Jim D on 3rd Jun 2024

    One of the best constructed Bolt Carrier Groups I have used. Period. I have several tested and proven BCG's and trust all of them. I decided to give this one a try after some research, and it did not disappoint. I had a 13.7 that was a little finicky with Buffer weight, ammo, ect. It was a constant adjustment of the Gas Block. I tried this shortly after receiving and it functioned flawlessly. All rounds from weak Steel .233 to full Brass .556 ran great. The BCG that was in there was a trusted BCG brand, which I will not name. This one is a bulletproof design and well made. Follow instructions and degrease the unit when it comes in, then lube. It has a sticky grease coating when new. I disassemble all new BCG's anyway to examine them and see what they are made of. This one rocks. Great, tight tolerances.

  • 5

    Great BCG

    Posted by Brock on 5th Apr 2024

    This is my second purchase of this BCG. They are great and at a great price. Shipping is very fast. Great company to do business with. The next time I need parts I will be ordering from them.

  • 5

    Premium BCG

    Posted by Shane Martin on 21st Mar 2024

    Out of the box this thing is flawless absolutely can tell the difference from a standard BCG exactly what I was wanting and arrived in great time

  • 5

    Microbest BCG

    Posted by Brock on 20th Mar 2024

    Theses are great BCG's and an excellent price!

  • 5


    Posted by Jared on 6th Feb 2024

    All you need in a BCG. Good price. Fast shipping

  • 5

    Microbest phosphate +

    Posted by Cameron Mills on 1st Feb 2024

    First off I would like to say how fast Arftac sent out my package And how fast I received it! I don't think I've ever gotten order that fast! I ordered on a Sunday night and originally got the nitride but sent email and within 5 min they got back to me and changed the order. Bcg checks all the boxes and great price. Feels solid and has great reputation I can't wait to fire my gun with it.

  • 5

    Microbest phosphate+ BCG

    Posted by Bangkok_Dangerous on 23rd Jan 2024

    This bcg checks all the right boxes. Phosphate w/chrome, sprinco springs, and the ocks gas key screws properly staked was just icing on the cake. Basically the same as Sionics, Solgw/fcd bcg that I was looking at before I found this gem. I did install the fcd/sotar np3 cam pin on mine. It’s not needed just personal preference. Will definitely buy more when I get a chance to. Also, if you have any dogs leave a note in the comments section and they might throw in a treat for them. Great company to deal with. Order with confidence.

  • 5

    Microbest phosphate+ BCG

    Posted by Zach B on 20th Jan 2024

    Already had the chrome premium BCG (big fan) so I decided to try the phosphate + version. Initially received one with a damaged gas key port, but I notified customer service and they sent me a new one ASAP, along with a prepaid return label. New one arrived in perfect shape and I’m looking forward to testing it out!

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