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What is an 80 lower?

Posted by 80-lower on Aug 28th 2017

What is an 80 lower?

What is an 80 lower? That’s a simple question, with a somewhat longer explanation. When it comes to firearms when people say the phrase ‘lower’ it generally means a "lower receiver". A lower receiver, in general, is the part of the firearms that houses the bolt, firing, mechanism and generally the action of a firearm. Generally lower receivers refer to AR 15 lower receivers. An AR 15 lower receiver houses the fire control group, the magazine well, and connects the buffer assembly to the weapon.

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So, What is an 80 Lower?

  • A partially completed lower receiver (80% completed)
  • No fire control group pocket cut or any fire control group holes drilled
  • Legally, NOT a firearm
  • No Federal Firearm License (FFL) Required
  • Available for AR-15s and AR-10 platforms

ATF Explanation of an 80 lower

In terms of firearm laws, a lower receiver is the only part on a rifle that is actually considered a firearm. according to the BATFE. The lower receiver is the serialized portion and falls under all the necessary gun laws. When purchasing an already completed AR lower receiver, you have to go through a Federal Firearm License Transfer (FFL Transfer), even when ordering online. This means going through a background check, having to fill out a 4473, pay the FFL for the transfer and background check, and deal with any arbitrary waiting periods.

80 Lower Clause

This is where we step in with that 80 moniker in 80 lower. An 80 lower is an unfinished lower - "80" meaning it is 80% percent complete. To turn an 80% lower into a 100% lower you have to mill out the fire control group. Further information on "How to Complete an 80% Lower" can be found here:

Before you start milling the 80 lower out, it is not considered a firearm. In fact, under the eyes of the law, it is basically just a hunk of aluminum. This allows you to bypass an FFL and have shipped directly to your home! You can build an AR-15 without a 4473, and do it at home.

You can build your own firearm in the United States, there are no laws against this. In general, you cannot create firearms with the intent to sell them without have the proper license. Building firearms for personal use is completely legal. An 80 lower gives you a simplified platform to building a modern, semi-automatic rifle. Just remember, as soon as you begin milling out the fire control group, the 80 lower is considered a firearm and is bound by State and Federal firearm laws.

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Building Your Own AR-15

Finishing an 80 lower allows you to take one step further into the effort of creating a rifle. Is it easy? Not exactly, but it is not difficult. It is challenging. Building an AR-15 from an 80 lower is challenging, and therefore is rewarding. It requires you to know how to run the proper tools, and the know how to be a safe power tool user. An 80 lower saves your money, time, and allows to build the rifle of your dreams.

You also have the additional benefit of being able to tailor a rifle to your exact specifications. You can build an AR 15 as a carbine, a full sized rifle, a pistol, or a special purpose rifle. It all starts with an 80 lower, and the will to get it done.

If you are ready to build your rifle, browse our selection of 80 lowers and start your AR 15 build today:

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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.