Microbest

Microbest AR15 5.56 C158 MPI All-Chrome Bolt Carrier Group, Premium COSMO (Read Description)

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MSRP: $199.99
$129.99
You save $70.00
Microbest AR15 5.56 C158 MPI All-Chrome Bolt Carrier Group, Premium COSMO (Read Description)
Microbest AR15 5.56 C158 MPI All-Chrome Bolt Carrier Group, Premium COSMO (Read Description)
SKU:
MB-BCG-556-CHR-ACP-PREMIUM-COSMO
MPN:
MBEST-BCG-556-CHR-ACP-PREMIUM-COSMO
Maximum Purchase:
3 units
Current Stock:

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Description

***Cosmetic Blemish*** These are the same spec as our PREMIUM BCGS. They will function properly 100% of the time but may exhibit cosmetic irregularities. 

 

The Ultimate Hard-Use 5.56 Bolt Carrier Group:

These aren't designed to be pretty. They're not meant to compete with the gorgeous museum-quality $200+ units that other well-respected manufacturers are putting out. But this is not just another component; built to exceed military specifications, our bolt carrier group is designed to be the hard-use always-performing heart of your AR-15. It just happens to look pretty darn good.

 

***These are All-Chrome Except for Phosphate Gas Key and Extractor***

-Phosphate Extractor

-Phosphate Gas Key

-Sprinco 5-coil Extractor Spring and Sprinco Ejector Spring

-OCKS Fasteners, Properly Staked

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.

Features:

All-Chrome M-16 BCG, Phosphate Gas Key and Extractor

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)
  • Chrome Silicon Ejector Spring by Sprinco

Mil Spec Extractor - PHOSPHATE 

  • 4140 Steel
  • Chrome Silicon Extractor Spring by Sprinco
  • Black Extractor Insert

Mil Spec Gas Key - PHOSPHATE

  • 4130 Steel
  • Optimized Carrier Key Screws (OCKS) provided by Michiguns
  • Properly Staked
  • Mil-Spec Opening Verified and Optimum Alignment Checked

Weight: 11.6oz

Customer Reviews

3 reviews

  • 5

    Microbest BCG

    Posted by Michael on 19th May 2025

    This BCG configuration cannot be beat, especially for the price. I've always sourced parts for this configuration individually, and I wish I had found ARFTAC sooner, because you cannot build this anywhere close to what it's being sold here for, plus no more fighting with extractor spring pockets or surfacing gas keys and staking(which theirs is perfect) Also, comes with a sticker.

  • 5

    Product

    Posted by Gio V on 21st Feb 2025

    Best BCG you can ask for and delivery was quick

  • 5

    Not Pretty, But gets the job done!

    Posted by HB on 18th Feb 2025

    Just got in this Premium Cosmo (BLEM) BCG. The carrier has a dull nickel type look to it as if a layer of chrome plating was missed. A few scratches on the none-ejection side but nothing deeper than the plating. I have the regular premium and side-by-side the regular one has a far "shinier" and deeper chrome finish. It is just prettier. The bolt itself is 100% with no issues on it. For the price this is an amazing value as the BCG will spend it's entire life inside the upper anyways. Great buy!

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