Push your .300 Blackout build to its practical limits with this precision-focused, stainless, fluted heavy-barrel upper engineered for shooters who demand consistent performance on steel at distance.
The 16" barrel forged from 416R stainless steel delivers optimal velocity for the caliber while keeping your build non-NFA, giving you the ballistic advantages of a longer tube without the hassle of a tax stamp. The heavy contour and fluting enhance rigidity and thermal stability, helping maintain accuracy through extended strings.
This upper ships assembled and ready to install on any finished lower receiver assembly (sold separately).
What’s Included
This is not a firearm. It includes an assembled upper receiver, bolt carrier group, and a charging handle.
300 BLK Upper Assembly Specs
Barreled uppers are assembled in-house before shipment.
Barrel
- Chamber: .300 AAC Blackout
- Contour: Heavy, Straight Flutes
- Length: 16”
- Twist Rate: 1:8
- Gas System: Carbine
- Gas Port: 0.750”
- Muzzle Threads: 5/8x24
- Material: 416R Stainless
- Finish: Nitride
- Lining: Stainless
- Extension: M4
- Muzzle: Twisted Flash Hider
Handguard
- Attachment System: 12" M-Lok w/ Split Top Rail
- Finish: Type III Hardcoat Anodized (Mil-Spec)
- Top Rail: M1913 Picatinny
- Material: Billet 6061-T6 Aluminum
- Attachment: Barrel Nut
Upper Receiver
- Profile: M4 Flattop
- Material: Forged 7075-T6 Aluminum
- Finish: Type III Hardcoat Anodized (Mil-Spec)
Bolt Carrier Group
- Profile: M16/Full-Auto
- Steel: 9310 Tool, HPT/MPI-tested
- Exterior: Black Nitride
- Interior: Black Nitride
- Gas Key: Staked
- Charging Handle: Included
Lower receiver not included.
WARNING: Handling firearms parts and accessories can expose you to lead and other petroleum products known to the State of California to cause cancer and reproductive harm. For more information go to: www.P65Warnings.ca.gov
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GunBuilders.com only ships within the United States. Federal legislation dictates we cannot ship our products internationally.
