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What is an AR-15 Stripped Lower Receiver? What’s an 80% Lower?

What is an AR-15 Stripped Lower Receiver

Building your own AR-15? You’re likely doing a little research as you read this. If you searched enough, you’ve come across the terms “stripped lower receiver” and “80% lower.”

So, what is all this stuff? Why does the receiver even matter? This is your beginner’s guide to understanding the most important part of America’s favorite rifle.

The AR-15 Stripped Lower Receiver

The AR-15 stripped lower receiver is the empty aluminum or polymer housing that holds the trigger, safety, lower parts kit, buffer system (buttstock, tube, spring, and buffer), and the magazine. Think of it as the “foundation” for the lower half of the rifle. Once assembled, the lower and upper receivers meet and attach with two removable pins.

BIG important legal note! The stripped lower is the only part of the AR-15 that’s legally considered a firearm. To buy one, you need to fill out the NICS paperwork at your local gun store or FFL, pay the fees, and provide ID. Just like if you were buying a rifle or handgun. Yes, even though this thing’s an empty aluminum bucket of sorts, the law treats it no differently than a loaded up rifle with a 30-round magazine, hammer cocked.

The good news: You can buy literally every single part needed to make a rifle (including a ready-to-fire upper receiver, or even a complete build kit) without needing an FFL, background check, or any fees and paperwork. This is just one of many reasons why gun owners love the AR-15: It’s so easy to build one because you can legally buy almost everything you need, sans the red tape.

The 80% Lower Receiver

80% Lower Raw (1-pack)

You know how we just said you can buy almost everything you need to build your AR-15 without the extra hassle and cost? The “almost” part gets solved with the 80% lower receiver. The 80% lower is a receiver blank, an unfinished AR-15 stripped lower receiver that the end user finishes at home.

We’ll explain more in a second. To truly appreciate the 80 lower, you first need to know two things. One is the Gun Control Act of 1968, and the other is… This guy:

This is California Senator Kevin de Leon.

Senator Leon made himself – and the 80% lower – famous back in 2014, when he coined the term “ghost gun”. If you want a laugh, watch the quick clip.

Senator Leon was unhappy about the fact that any American citizen (who isn’t a felon) can legally build a gun at home using something the Bureau of Alcohol, Tobacco, and Firearms (ATF) calls a receiver blank.

Like we said in the beginning, we call these receiver blanks, “80% lower receivers”.

The Gun Control Act of 1968

That legal right came from the Gun Control Act (GCA) of 1698.

The GCA says yes, you can build a gun at home. No paperwork required, no serial number, no background check, no taxes, no fees. The firearm in question must be for personal use.

The ATF even backs it up:No, a license is not required to make a firearm solely for personal use. However, a license is required to manufacture firearms for sale or distribution. The law prohibits a person from assembling a non–sporting semiautomatic rifle or shotgun from 10 or more imported parts, as well as firearms that cannot be detected by metal detectors or x–ray machines. In addition, the making of an NFA firearm requires a tax payment and advance approval by ATF.” [18 U.S.C. 922(o), (p) and (r); 26 U.S.C. 5822; 27 CFR 478.39, 479.62 and 479.105]

This is a complete guide on all 80 percent lower laws, including state and federal.

Turning an 80% lower into a stripped lower

If you’re wondering, “What’s the benefit to all this?” Consider what it normally means to buy a gun:

AR-15 80 Lower with Buffer Assembly - Blog Photo 3

Would you rather wait an hour while that background goes through? Or…

Would you rather spend that hour by immediately building your AR-15?

How about that $20 NICS fee, the $35 transfer fee, or the 10% sales tax? The $150 firearm application, if you live in a restrictive state? Or…

Would you rather spend that money on gun parts and gunsmithing tools?

Why AR-15 owners choose to buy a receiver blank:

  • They don’t have to pay firearm taxes or fees
  • An 80% lower doesn’t need a background check
  • They don’t have to give up or register their information
  • They can buy everything they need online and it ships to them

Completing an 80 lower

Completing 80% lower with the appropriate gunsmithing tools and a jig (a metal cutting and drilling template) will take around one to three hours. Even if you’ve never machined metal, this project is pretty easy. The 80 lower was designed so that amateur gunsmiths and the average gun owner can complete this project at home with some basic tools.

Extra gunsmithing tools needed:

  • 80% lower jig
  • 5/32” Drill Bit
  • 3/8” Drill Bit
  • 5/16” Drill Bit
  • 3/8” End Mill
  • Handheld Router
  • Handheld Drill or Drill Press
  • Tabletop or Drill Press Vise
  • Machining Oil / Cutting Fluid
  • Canned Air and Brush
  • Ear and Eye Protection

How to Complete an 80% Lower

If you’re more than a curious reader and you want to build a black rifle (or pistol) from scratch, stick around!

This is a complete guide on how to complete an 80% lower receiver using a jig, and a router or drill press.

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 80Lower Jigs, 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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