300 Blackout Rifle Kits

300 Blackout Rifle Kits

We put together a selection of affordable, easy-to-complete 300 Blackout Build Kits so you can avoid those high prices at the local gun store. These AR-15 pistol and rifle kits include a top-of-the-line 416R stainless or mil-spec 4150 steel barrel for MOA accuracy. Each kit features an optional billet or forged 80% lower. 

300 Blackout is an incredibly versatile round, offering medium-range accuracy with supersonic loads, and whisper-quiet shot placement with subsonic loads. Enjoying all that performance means investing in a quality build kit, which you can find right here.

What’s Included

To ensure reliable performance, every 300 Blackout upper in each kit is pre-built and ships ready to fire out of the box. Each Build Kit includes every part you need to complete your rifle or pistol:

  • Complete upper receiver assembly
  • Carbine or pistol gas system
  • AR-15 lower parts kit
  • Complete buffer assembly
  • Butt stock (rifle) or pistol brace
  • M16 full-auto bolt carrier group

Finish Your Build with an 80% Lower

Select an optional billet or forged 80% lower when you pick your build kit, and you’ll have every part you need to finish your rifle or pistol. Just pick an AR-15 80% jig from our available options, and you can complete your build in a single day.

Benefits of Our 300 Blackout Build Kits:

  • Complete AR-in-a-box (w/ 80% lower)
  • Not considered a firearm, no FFL required
  • Pair with optional billet or forged 80% lower
  • Kits are compatible with any AR-15 80% jig
  • Ships straight to your front door
  • Backed by Lifetime Warranty
  • Proudly built in the U.S.A.


DISCLAIMER: If you are new to the world of DIY gun building, you likely have a lot of questions and rightfully so. It’s an area that has a lot of questions that, without the correct answers, could have some serious implications. At 80-lower.com, we are by no means providing this content on our website to serve as legal advice or legal counsel. We encourage each and every builder to perform their own research around their respective State laws as well as educating themselves on the Federal laws. When performing your own research, please be sure that you are getting your information from a reliable source.

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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.