.300 Blackout AR-15 Pistol Kit (8.5” Barrel & 7” MLOK Handguard) with 80% Lower (1:8 Twist)



Put some more oompf in your home defense with this AR-15 pistol build kit!  Being a short little AR, it’ll move around the corners of your home nicely, and being chambered in .300BLK, you’ll have the choice of either supersonic or subsonic rounds, subsonic being one the .300BLK excels at.

This build kit gets you everything you need to get ‘er up and running except mags and ammo.  We also don’t include BUIS or optics, since these are highly personal choices to people. You get a pre-built upper assembly with an 8.5” barrel chambered in .300BLK coupled with a 7” lightweight M-Lok handguard.  The lower half of this awesome build kit gets you the SBA3 adjustable pistol brace by SB Tactical and an MOE grip by Magpul.

AR-15 Pistol Build Kit Specs:

Barrel Length: 8.5″

Barrel Steel: Chrome Moly Vanadium

Barrel Finish: Phosphate

Muzzle Thread: 5/8 x 24

Chamber: .300 AAC Blackout

Twist Rate: 1:8

Muzzle Device: A2 Flash Hider

Receiver Material: 7075 T6 Forged Aluminum

Receiver Type: M4

Handguard Type: 7” Lightweight M-Lok

Bolt Carrier Group Included: Yes

Bolt Steel: Carpenter 158

Charging Handle Included: Yes

AR-15 Pistol Build Kit Features:

  • Complete build kit w/ optional lower
  • Includes pre-built .300BLK AR upper
  • High-quality CMV barrel for accuracy
  • Features enhanced, polished trigger
  • Not considered a firearm, no FFL required
  • Proudly built in the U.S.A.
  • Backed by Lifetime Warranty

Barrel: Phosphate-coated, 8.5”, chambered in .300BLK. Made of 4150 CMV steel. Heat-treated. Features 1:8 twist rate. Includes 7” M-Lok handguard, and A2 flash hider.

Upper: Made of 7075 T6 forged aluminum. Hard-coat anodized (Type III).

Bolt: Heat-treated. Nitride finish. Carpenter 158 steel.  Full auto profile.

80% Lower: Complete with optional AR-15 80% lower. Mil-spec fittings. Type III Hardcoat anodized finish.

Lower Parts Kit: Mil-spec AR-15 lower parts kit. Enhanced, polished trigger (EPT). Six-position buffer tube. SB Tactical Pistol Brace. Magpul MOE grip. Carbine buffer spring and pistol buffer.

Charging Handle: Standard AR-15 charging handle.

Please note: If completing your AR-15 build using the optional 80% lower, please select an AR-15-compatible 80% jig from the available options on our website.

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.