BCM® Standard 12.5" 300 BLACKOUT Complete Upper Receiver Group w/ KMR-A10 Handguard

MSRP: $1,081.50
Your Price: $803.45
(You save $278.05 )
300 BLK
Barrel Length:
Barrel Style:
Stock Status:

Out of stock

About the BCM® Standard 12.5" 300 BLACKOUT Complete Upper Receiver w/ KMR-A10 Handguard

  • Continuous taper barrel profile designed for optimal weight, balance, and performance.
  • Barrel profile fluted toward the rear near chamber area - Increases strength and heat dissipation.
  • Tapered barrel profile out front, for easier maneuverability.
  • No sharp handguard cap shoulder for improved barrel harmonics and improved accuracy.
  • Muzzle threaded in standard 30 cal (5/8x24).

Whats included:

  • Includes KMR-A10 KeyMod™ Handguard.
  • Includes KMSM (KeyMod™ Sling Mount)
  • Includes One 3" Picatinny Rail Section
  • Includes BCM® Comp Mod 1 - 762/300 BLK
BCM® has taken great care to ensure the best possible performance and interchangeability. However, due to the large operational range of 300 Blackout ammunition in the market place, BCM® cannot guarantee function will all ammunition types in all conditions. These barrels were designed to run with a H3 buffer with high velocity ammo.
If running subsonic ammunition, it is recommended to run your suppressor and a carbine buffer. Fine tuning may be required in limited instances based on ammo and buffer choices that work best for the desired application. BCM® also recommends running the Crane O-ring (provided with all BCM® Bolt Carrier Groups) over the extractor with 300 Blackout.


  • Caliber: 300 Blackout
  • Barrel Length: 12.5"
  • Barrel Material: 11595E Spec Steel
  • Barrel Finish: Manganese Phosphate (Mil-Spec A-A-59267)
  • Bore & Chamber: Chrome Lined
  • Weight: 2.5 lbs
  • Twist Rate: 1:7
  • Gas System: Pistol
  • Muzzle Device: BCM® Comp Mod 1 (762/300BLK)
  • Muzzle Threads: 5/8x24
  • Handguard: KMR-A10

Shop Related Products:

Want to see more upper receivers? Click the links below to view more BCM® AR complete uppers!


Bravo Company builds: Life Saving Tools™
Copyright 2023 Bravo Company MFG, Inc.
***This product contains chemicals/materials known to the State of California to cause cancer and other reproductive harm. To learn more, visit www.p65warnings.ca.gov.***

13 Reviews

  • 5
    Customer review

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  • 5
    Customer review

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  • 5
    BCM Does it again.

    They never fail to amaze me. I absolutely love BCM. Fast shipping, excellent quality. Best price for the quality. I trust my life with my BCM gear.

    I served in the Marines as a infantry man than A MOUT Instructor, I was awarded the opportunity to handle a lot of weapon platforms.

    I came across BCM a few times and was extremely impressed with the quality of the Machine work. The accuracy is right up there with the quality as well.

    I own 6 BCM uppers, and I will always be a patron of the company.

    Thanks guys.

  • 5

    As usual ..... my experience with BCM with my 300 blackout upper was excellent. I have been ordering rifles and accessories from BCM for years and will continue to do so.

  • 5
    Quality Upper, Would Recommend

    BCM is a name you can trust period! The upper was just as described and well built. I am more than satisfied. Customer for life.

  • 5
    300 BLK upper

    Quick service, customer service second to non. Top quality product, and the company that shows proud in their product and in their customers. Will remain a loyal customer for future purchases.

  • 5
    BCM 300 Black Upper Assembly

    BCM products are good looking, well made and milspec. Any more and you're paying for bling. Any less and you're buying junk. Barrels are the right steel, properly lined, the right twist, the right finish, have the M4 feed ramp and are HPT/MPI. This is the third upper assembly (with bolt/carrier group) I've purchased from BCM. Flawless every one. The only variable I've faced was selecting the proper buffer weight for the shorter barrels.

  • 5
    Can't wait to complete my SBR build with this uppe

    The quality of this complete upper receiver is 2nd to none. This is my first AR-15 build and after receiving such a great product from Bravo Company I'm spoiled now. Thank BCM. Keep up the great work

  • 5
    Outstanding product

    I like y'alls products