What are 80% Lower Receivers?

80% lowers such as 80% AR-15 Lower Receivers are items that have not yet reached a stage of manufacture to be considered a firearm.

Some 80% AR-15 Receivers
Some 80% AR-15 Receivers

The term “80%” is actually just industry slang and not something endorsed/used by the ATF (Bureau of Alcohol, Tobacco, & Firearms).

We’ll cover some common FAQ’s, other examples of 80% lowers besides AR-15’s, and recommended manufacturers.

Disclaimer: I am not a lawyer and this is not legal advice.  Be sure to check all your local, state, and federal laws.

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Are 80% lower receivers legal?

They are legal to own since they do not meet the definition of a firearm under the Gun Control Act of 1968 (GCA) and are often referred to as “paperweights.”  Just be sure that the manufacturer of your 80% has an ATF “determination letter” that specifically states their paperweight is not a firearm.

AR-15 80 Receiver Side, ATF
AR-15 80 Receiver Side, ATF

Here’s some more from our end.

80% AR-15 Lowers, All Sides
80% AR-15 Lowers, All Sides

Do I need to be an FFL to make a firearm?

The short answer is no as long as you meet the following criteria:

  • Can legally own a firearm in your state/county/city (not a felon, etc…)
  • Manufacturing only for personal use
  • Configuration is legal in your state/county/city (National Firearms Act rules apply for short barreled rifles, automatics, etc…)

Do I need to put a serial number?

You as a private individual making a gun for yourself do not need to put a serial number.  However, it’s helpful to have one in case it gets lost or stolen.

Why are they silver in color?

Most 80% lowers are sold as raw aluminum but you can also find some anodized which is the standard coating.  However, when you complete an anodized 80%, all your cuts will expose the aluminum underneath.  Therefore we recommend going with a raw lower and finish it afterwards.

Once you complete your lower, you can have it anodized or coated in other popular coatings such as Duracoat, Alumahyde, or even just spray paint if you’re feeling fancy.

How hard is it to finish an 80%?

You’ll need some specialized equipment such as a drill press or mill and some bits, but an 80% AR-15 lower receiver is very doable for someone who has patience and some mechanical inclination.  The AR-15 lower is quite forgiving since you are only machining out the pocket for the trigger and some pin holes.

AR-15 80 Receiver Drilling, CNCGuns
AR-15 80 Receiver Drilling, CNCGuns
AR-15 80 Receiver Milling, CNCGuns
AR-15 80 Receiver Milling, CNCGuns
AR-15 80 Receiver Finished, CNCGuns
AR-15 80 Receiver Finished, CNCGuns

*Update* Now you no longer need a mill or even a drill press…you only need a router and regular drill.

Easy Jig 2 and Lowers
Easy Jig 2 and Lowers

Check out our favorites in Best 80% Jigs.

250
at 80% Arms

Prices accurate at time of writing

Prices accurate at time of writing

Boom!

Finished 80% Lower with Easy Jig 2
Finished 80% Lower with Easy Jig 2

What are common 80% examples?

AR-15 80% Lower

The most common 80% lower receiver project out there.  We recommend going with the leading manufacturer Tactical Machining.  Their Gen 2 80% has the rear lug already cut out which saves you a little time.

80 AR-15 Lower Receiver, Tactical Machining
80 AR-15 Lower Receiver, Tactical Machining
80 AR-15 Lower Receiver Rear Lug Cut, TM
80 AR-15 Lower Receiver Rear Lug Cut, TM

AR-10/.308 80% Lower

The big brother of the AR-15, the AR-10 is another 80% project that is becoming more popular.  It is very similar to the AR-15 in terms of difficulty.  Again, we recommend the 80% from Tactical Machining.

80 .308 AR-10 Lower Receiver, TM
80 .308 AR-10 Lower Receiver, TM

10/22 80%

The 80% lower version of Ruger’s venerable 10/22 also from Tactical Machining is rarely in stock and has some more difficult steps since the barrel will mount directly to the receiver.

80 TM-22
80 TM-22

1911 80% Lower

Tactical Machining‘s newest 80% lower is the 1911.  The difficulty level is quite high since you’ll be machining the slide rails which need to be near perfect.  Almost all the other pieces of the 1911 also need to be hand-fit.  They currently sell out in a few hours whenever they come into stock.

1911 80 Lower Receiver, TM
1911 80 Lower Receiver, TM

How do I complete an 80% lower?

We’ll be coming out with step-by-step 80% lower guides soon!

Sources:

10 Leave a Reply

  • Rick

    Very interesting article. When does the "step by step " come out?

    1 year ago
  • Matt

    It is illegal to assemble an 80% in NJ. It is considered manufacturing a firearm., specifically forbidden by state law.

    2 years ago
  • Peter Bovey

    In California, it seems we do have to add a serial # to any 80% build.

    2 years ago
  • Mike klein

    Great article, very informative, but I have a Question, how many 80 percent receivers are you allowed to build, Is there a limit? Thanks for all the great info, Mike klein

    2 years ago
  • Bruce W

    I have gotten into the 80% build for AR15 and 1911. Its lots of fun to build your own. Good info. Article is kind of an ad for Tactical Machining. There are lots of Other quality suppliers too. Im a fan of 80% Arms. Keep up the good work Eric.

    2 years ago
  • Brian P.

    Dont have anyone work on our non-registered firearm... Simple, true story

    2 years ago
  • Matthew Johnson

    Once you complete a lower, you mention that you can have it anodized or coated in other popular coatings such as Duracoat or Alumahyde. My question is where can someone have this done? Is it still legal if you have someone else do the work, or will I need to figure out how to finish it on my own? Thanks!!!!

    2 years ago
    • Eric Hung

      Hey Matthew, you'll have to call/search around. Some are FFL's so it could count as repair. Otherwise I believe you might have to wait there.

      2 years ago
  • A. Swift

    I don't build them because of big brother. I do them for the project and satisfaction. Heck, I have made several $700 guns for $1000 each. Definitely not the project for the budget minded.

    2 years ago
  • Michael Eder

    Hello all. I guess I don't understand the 80% build out if your concern is that big brother knows what you have. Of course if you purchase new AR it goes through an FFL and record is made of you purchasing that particular rifle..... however, at least here in Pa, there is no requirement to use FFL to privately re-sell a non-NFA rifle and so should a day come when big bro says hand them over, the gov has no way to know what you still own or have sold.

    2 years ago
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