Check out this wicked little 300 BLK pistol upper: It features a 9" M-LOK "honeycomb" rail measuring just a hair longer than the 8.5" barrel, providing that sleek locked-up look when you thread on a can. Or, just roll with the provided "can"-style flash hider. It looks great and helps tame those fireballs.
Our 300 BLK pistol uppers and test-fired and cycled to ensure reliability when running supersonic and subsonic ammo. Pair it up with your favorite lower, or use it to complete a custom build! Check out our lower assembly components to make things easy.
PLEASE NOTE: This is not a firearm. This is a prebuilt upper assembly only. It includes an assembled upper receiver, bolt carrier group, and charging handle.
New to ARs? Here's how to build an AR-15.
AR-15 Rifle Upper Assembly Specs
Barreled upper assemblies are assembled in-house before shipment.
Barrel
- Chamber: .300 AAC Blackout
- Contour: Straight
- Length: 8.5”
- Twist Rate: 1:7
- Gas System: Pistol
- Gas Port: 0.750”
- Gas Hole Dia.: 0.070”
- Muzzle Threads: 5/8x24
- Feed Ramps: M4
- Material: 4150 CMV
- Finish: Nitride
- Process: Button Rifled
- Lining: None
- Extension: M4
- Muzzle: "Can"-style flash hider
Handguard
- Attachment System: 9" M-Lok, Skeletonized
- Finish: Type III Hardcoat Anodized (Mil-Spec)
- Top Rail: M1913 Picatinny
- Material: Billet 6061-T6 Aluminum
- Attachment: Barrel Nut
Stripped 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: Carpenter No. 158 (Mil-Spec)
- Exterior: Black Nitride
- Interior: Black Nitride
- Gas Key: Staked
- Charging Handle: 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
Shipping of various parts and/or accessories are prohibited to states and locales (ie New Jersey, California, New York, etc…) with restrictions against certain parts and/or accessories or "assault weapons" (i.e. states with high-capacity magazine restrictions, manufacturing of semi-automatic weapons, etc..). It is your responsibility to be aware of your local firearms laws before purchasing from our website or machining a firearm. We try our best to keep our shipping page current, but laws change daily.
GunBuilders.com only ships within the United States. Federal legislation dictates we cannot ship our products internationally.
