July 4th Sale - Use Coupon: 1776

BG 4.5" 9mm Upper Receiver - Black | FLASH CAN | 4.25" M-LOK | Without BCG & CH

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Product Code: BGBU-459MM425FC-BLK
MSRP: $364.95
Sale Price: Sale Price: $149.95
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Builder's Grade 4.5" 9mm Upper Receiver - Black | FLASH CAN | 4.25" M-LOK | Without Bolt Carrier Group and Charging Handle

This 4.5 inch M-LOK upper receiver comes with a 4.25 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 making the action smooth and easy to keep clean.

Caliber 9mm
Length 4.5
Material 4150 Chrome Moly Vanadium
Profile Straight
Finish QPQ Corrosion Resistant
Gas System Length None
Gas Block Journal N/A
Dimpled? No
Twist Rate 1:10
Muzzle Thread 1/2x36 TPI
Weight 8.3oz
Barrel Extension Integrated
Target Crown 11 Degree


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


  • 4.25" free float handguard
  • MIL-STD 1913 Picatinny rail on top
  • 1 M-Lok slots on 3 sides
  • Precision Machined 6000 Series aluminum, for high strength and weight savings
  • Steel Barrel nut to resist movement under heat
  • Made in USA


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.***