Microbest BCG+ Phosphate/Chrome Lined OCKS C158 HPT/MPI 5.56 Bolt Carrier Group
Original price was: $139.95.$92.00Current price is: $92.00.
Microbest BCG OCKS C158 HPT/MPI 5.56 Bolt Carrier Group – Phosphate/Chrome-Lined
90 in stock
90 in stock
Microbest BCG Mil-Spec OCKS C158 HPT/MPI 5.56 Bolt Carrier Group – Phosphate/Chrome-Lined
Estimated Ship Date 6/24/26
The Microbest BCG has been designed from the ground up with the most avid shooters in mind, using only the best materials available on the market today.  The bolt assembly is machined from Carpenter No. 158® steel, shot-peened, MP marked, HP tested, and has a tool steel extractor that is machined from bar stock. Microbest is the OEM manufacturer and supplier of bolt carrier groups for a lot of popular rifle manufacturers, including but not limited to, Bravo Company Mfg and Sons of Liberty. Microbest is trusted to build a bolt carrier group that exceeds the MIL requirements from the right materials and processes with great attention to details
Upgrades Included Now:
- OCKS Gas Key Screws, Properly Staked by Microbest
- Sprinco 27001 5 Coil Extractor Spring
- Sprinco Extractor Insert
- Sprinco 27001 Ejector Spring
Bolt Assembly:
- Bolt precision machined from Carpenter 158 alloy and vibratory tumbled
- Heat-treated and shot-peened
- Individual high pressure/proof (HP) and individually magnetic particle inspection
- Extractor from 4140, heat-treated and shot-peened
- Ejector from S7 tool steel, heat-treated and shot-peened
- 5 Coil Sprinco Extractor Spring
- Sprinco Ejector Spring
- Gas Rings 3 Mil-Spec
- Phosphate finish
Carrier:
- Machined from AISI 8620 steel
- Full-auto M16 profile
- Heat treated and Carburized/strain relieved
- Precision ground gas key interface
- Manganese phosphate finish with hard chrome interior
- Gas key from 4140 steel with chrome interior
- OCKS Gas Key Screws, Phosphate Coated
Misc:
- Cam pin from 4140 chromoly steel, heat-treated
- Firing pin from 8640 steel alloy, heat-treated, hard-chrome plated
- Firing pin retaining pin from 1038 carbon steel, heat-treated
ADDITIONAL INFORMATION
WEIGHT – 15 oz
BOLT MATERIAL – Carpenter 158 Steel
CARTRIDGE COMPATIBILITY – .223/5.56 NATO/.300 BLK
FINISH – Mag Phosphate
CARRIER PROFILE – M16
HIGH PRESSURE TESTED – Individually HP Tested
MAGNETIC PARTICLE INSPECTED – Magnetic Partical Inspected
PLATFORM – AR-15
BOLT FINISH – Mag Phosphate
Additional information
| Weight | 15 oz |
|---|
Ricky38108@gmail.com (verified owner) –
Same bcg as my other high dollar ones except already upgraded and half the price. Must buy !!!
Dan ‘The Man’ Didgeridoo –
MicroBest, Sprinco, and Michiguns OCKS, for $99 out the door? Yes please! One of the best high performance, high value options available right now. Thanks Midwest Optics!
Hotdogjr (verified owner) –
Absolute quality at bargain prices. Got 2, phosphate finishes and machining are smoother than the Founding Fathers Microbest bcgs I got from PSA some years ago. The OCKS screws with staking biting into them really stand out, Sprinco springs all checked out. Great stickers, thx MWO.
Alexander (verified owner) –
I’ve bought three and plan on buying more
Eric (verified owner) –
Incredible BCG at an incredible price, will be buying more for later builds and spares.
pjendre (verified owner) –
Important info…
When I received it I was a bit reserved about the quality being there was no brass on the bolt face and the bolt marking MP was distorted which lead me to question it…I reached out to Microbest for information…
“All quality processes are done PRE photostatting”…being the HPT and MP testing. That put my mind to ease.
Reading on their website the different manufacturers they make BCGs for alot of things became clear on what I have read on reviews and forums about other bcgs, that they actually make…
Bottom like… a great replacement option (mine) or for a new build… I will be ordering more when they come back into stock..
Dave (verified owner) –
Great deal on this BCG. I will definitely be buying another when they come back in stock.
Jordan G (verified owner) –
Great Bolt Carrier Group! – The Microbest Bolt Carrier Group (BCG) is made from high-grade Mil-Spec materials and manufactured using precision machines.
When I received my bolt carrier group, I was happy to see that the gas key used Ned Christiansen’s OCKS to properly secure it. Also, the BCG includes sprinco extractor and ejector springs to enhance its reliability. Lastly, I gauged the bolt shoulder, gas ring, and bolt tail, and was happy to see that the carrier was gas-efficient.
The following are the results from my gauging. All are in inches.
Bolt carrier
Carrier – 6.685
Carrier key – .180
Bolt Slahoulder run – .529
Bolt gas run – .499
Bolt tail run – .251
Bolt
Bolt face – .380
Bolt shoulder – .5282
Bolt tail – .2505
Firing pin protrusion- .031
Bottom line is this. This BCG comes at an amazing price with solid upgrades right off the bat. I will definitely come back and get another one in the near future!
Erik G (verified owner) –
Bought one recently liking the upgrades, quality name and the good price.
Everything visually checks out.
Ran it through a gas key torque test and the both OCKS turned at around 25-30in lbs. I was quite surprised by this.