300 Blackout Pistol Kit (10.5” Phosphate Barrel & 12” Slant M-Lok Handguard) w/ 80% Lower (1:8 Twist)



For shooters who want to maximize their range, accuracy, and style points, we’re introducing the 10.5” 300 Blackout AR Pistol Kit. This A2-profile barrel features a pistol-length gas system and is optimized for handling supersonic and subsonic 300 BLK cartridges with ease. We chose a 1:8 twist rate to provide reliable groupings with either loads, while the cold-forged 4150 CMV barrel goes to work guaranteeing MOA accuracy and incredible barrel life.

Out back, you’ll find a quality SBA Pistol Brace with a 5-position buffer tube. A carbine buffer works in tandem with an enhanced, polished trigger kit to ensure reliable cycling with any loads. Simply grab the optional forged or billet 80% lower, and you’ll have all the parts you need to turn a box of bolts and bits into a rugged, reliable AR pistol in a single day.

300 Blackout Pistol Kit Specs:

Barrel Length: 10.5″
Barrel Profile: A2
Gas System: Pistol-length
Barrel Steel: 4150 Chromoly Vanadium
Barrel Finish: Phosphate 
Chrome Lining: No
Muzzle Thread: 5/8-24
Chamber: 300 Blackout
Twist Rate: 1:8
Barrel Extension: M4
Diameter at Gas Block: .750
Gas Block Type: Low-profile
Muzzle Device: PSA Fluted Flash Can
Receiver Material: Forged 7075 T6 Aluminum
Receiver Type: M4
Handguard Type: PSA 12″ Slant End M-Lok Rail
Bolt Carrier Group Included: Yes
Bolt Steel: Carpenter 158
Bolt Carrier Profile: Full-auto
Charging Handle Included: Yes
Overall Length: 21″

300 Blackout Pistol Kit Features:

  • Includes all parts needed to complete build
  • Optional forged or billet 80% lower
  • Upper ships pre-built and test-fired
  • Enhanced, polished trigger for reliability
  • Not considered a firearm, no FFL required
  • Proudly built in the U.S.A.
No FFL required  Made in the USA  Lifetime Warranty

Shipping Restrictions

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

80-Lower.com only ships within the United States. Federal legislation dictates we cannot ship our products internationally.

We are a national retailer of individual components and not all products depicted on this website are legal in every state. Shipping of various products found on this website are prohibited to some states (such as California, Connecticut, District of Columbia, New Jersey, New York, Rhode Island, and Washington). The information, pictures, text or products presented on this website are not a representation by us, and should not be understood by you, that any product or completed firearm is legal to assemble or own in your state of residence. We encourage each and every builder to perform their own research about the state and federal laws that apply to them. It is your responsibility to understand the law and we encourage you to consult with an attorney or your local ATF representative.