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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 rifle kits include a top-of-the-line 416R stainless or mil-spec 4150 steel barrel for MOA accuracy. 300 Blackout is an incredibly versatile round. It offers 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.

300 Blackout Rifle Kits: What’s Included

To ensure reliable performance, every 300 Blackout upper is pre-built and ships ready to fire out of the box. Each kit includes almost every part you need to complete your rifle or pistol, minus an 80% lower receiver or stripped lower.  Here's what's included:

  • Complete upper receiver assembly
  • Carbine or pistol gas system
  • Mil-spec AR-15 lower parts kit
  • Complete buffer assembly
  • Magpul or M4-type buttstock
  • M16 full-auto bolt carrier group

Why our 300 Blackout Kits?

Not all AR build kits are created equal, and fabricating a reliable and accurate AR-15 chambered in 300 Blackout means getting the best parts. We work with the country's top firearm makers and gunsmiths to ensure each 300 BLK and AR kit we sell comes with the best mil-spec components, machined on the finest CNCs and forging equipment:

  • All barrels are forged from MIL-B-11595 E steel (4150 or Chromoly Vanadium)
  • All stainless barrels forged from Crucible 416R steel, offering sub-MOA accuracy
  • All BCGs are M16 in profile with chrome lining and properly staked gas keys
  • All stripped upper receivers forged from mil-spec 7075 T6 aluminum
  • All buffer assemblies and lower parts kits are mil-spec in fit and finish
  • All barreled uppers are test-fired to ensure proper assembly
  • 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, 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.

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, Hawaii, 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.