Description
Finally, there's an easy way for you to get up and running when it comes to the world of the .300 AAC Blackout AR-15. We put together this build kit just for you, the lucky shooter about to assemble a custom black rifle made for operatin'.
This build kit gets you a 16" stainless (match-grade) barrel with a 1:8 twist rate to accommodate the most popular .300 AAC supersonic and subsonic loads. You also get our ever-popular 13.5" free floating, lightweight M-Lok handguard. You supply the mags, lower receiver, and ammo (regular .223 / 5.56mm parts work perfectly with the .300BLK cartridge), and either sights or optics of your choice, and you're good to go.
What’s Included
This kit is not a firearm. It includes an assembled upper receiver, bolt carrier group, lower parts kit, and buffer assembly with buttstock. It does not include the component to make a firearm: A stripped lower receiver. Pair this rifle kit with an AR-15 80% lower receiver and AR-15 jig to fabricate a receiver, sold separately.
New builder? This guide explains 80 percent lowers.
AR-15 Rifle Kit Specs
Barreled uppers are assembled in-house before shipment.
Barrel
- Chamber: .300 AAC Blackout
- Contour: M4/Government
- Length: 16”
- Twist Rate: 1:8
- Gas System: Carbine
- Gas Block Dia: 0.750”
- Muzzle Threads: 5/8x24
- Feed Ramps: M4
- Material: 416R Crucible Stainless
- Finish: Stainless
- Process: Button Rifled
- Lining: Stainless
- Extension: .30-Cal
- Muzzle: A2 “Birdcage” Flash Hider
Handguard
- Attachment System: 13.5" M-Lok
- 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: Phosphate Coating
- Interior: Chrome-Lined
- Gas Key: Staked, Chromed
- Charging Handle: Included
Lower Receiver Parts
- Buffer System: Mil-spec, Carbine
- Buttstock: Mil-spec, M4-type
- Parts Kit: Mil-spec, single-stage
Receiver sold separately
No FFL or serialization is required to fabricate a receiver under federal law. However, state laws vary. Some states require serialization or have banned 80% lowers and gun-making kits. We encourage each and every builder to perform their own research about the state and federal laws that apply to them.


Shipping Restrictions
AR-15Lowerreceivers.com only ships within the United States. Federal legislation dictates we cannot ship our products internationally. 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 (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. We try our best to keep our shipping page current, but laws change daily.