BG Complete 4.5" 9mm Upper Receiver - Black | A2 | 4" M-LOK | With BCG & CH

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Product Code: BG459MM4INA2-BLK
MSRP: $405.95
Sale Price: Sale Price: $174.95
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Builder's Grade Complete 4.5" 9mm Upper Receiver - Black | A2 Flash Hider | 4" M-LOK | With Bolt Carrier Group and Charging Handle

This Complete 4.5 inch M-LOK upper receiver comes with a 4 inch free float handguard and is built with only the best Mil-Spec components. The heart of this upper is comprised of a 4150 barrel and our black nitride bolt carrier group that is finished with an incredible polish, making the action smooth and easy to keep clean.


  • Length - 4.5"
  • Material - 4150 Chrome Moly Vanadium
  • Profile - Straight
  • Finish - QPQ Corrosion Resistant
  • Gas System Length - None
  • Gas Block Journal - N/A
  • Twist Rate - 1:10 inches
  • Muzzle - 1/2x36 Threaded
  • Weight - 8.3oz

Bolt Carrier Group:

    • Colt & Glock Compatible
    • USA made 8620 Steel Carrier Construction
    • Phosphated or Nitrided Finish
    • Heavy Firing Pin Retaining Spring
    • 13.7 oz.

Upper Receiver:

This .22LR / 9mm upper receiver assembly is made from forged 7075-T6 aluminum and is Hard Coat Anodized. It meets military specifications and comes in a true slick side configuration. The ejection port door is sized for 9mm and 22LR. This upper does not have a shell deflector, nor does it have a forward assist.

  • Machined from a Mil-Spec 7075 T6 forging
  • Type III Hardcoat Anodized finish


  • 4" free float handguard
  • MIL-STD 1913 Picatinny rail on top
  • 1 M-Lok slots on 3 sides
  • Precision Machined aircraft grade aluminum, for high strength and weight savings
  • Steel Barrel nut to resist movement under heat
  • Made in USA

Charging Handle:

  • Alloy Charging Handle Assembly
  • Complete with Standard Latch
  • Made from hardcoat anodized aluminum
  • Black finish

Please Note: Uppers may present light fouling from our quality control process and/or test firing

***Please allow an additional 2-3 business days of lead time as these uppers are made to order.***