Building An 80% Firearm- Part 2, by Tupreco

Learn The Why and How (continued)

The key provision that makes the 80% industry possible is making sure that all the items being purchased and transported are parts and not a firearm. Because once the parts wind up in your hand, you have the right to now “make” a firearm as listed above but only if you can legally own that firearm in your state of residence.

Does this mean I can make my own firearm?

The short answer is “Yes, with conditions attached.” From the ATF website:

An individual may generally make a firearm for personal use. However, individuals engaged in the business of manufacturing firearms for sale or distribution must be licensed by ATF. Additionally, there are certain restrictions on the making of firearms subject to the National Firearms Act.

The second consideration is also critical: (again from the ATF website)

Does an individual need a license to make a firearm for personal use? 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.

So, you can’t sell it, ever. But when does a person need to become licensed? The simple answer is when they are considered “engaged in the business”. The following is once more from the ATF website:

Any person “engaged in the business” as a manufacturer must obtain a license from ATF. The term “engaged in the business” means— (A) as applied to a manufacturer of firearms, a person who devotes time, attention, and labor to manufacturing firearms as a regular course of trade or business with the principal objective of livelihood and profit through the sale or distribution of the firearms manufactured.

It is probably true that if you are simply a hobbyist, collector, sport shooter, or person not “engaged in the business” you would have wide latitude regarding how you built your firearms for your personal use. The reality is that you are in the big gray area. Many believe that the ATF likes it gray because it gives them wide discretion to take appropriate enforcement actions to go after those who they consider “engaged in the business” since that definition is fluid. Clearly, you may not have something as obvious as a corner storefront, website, or other method to sell your home-built plinker.

What about helping a buddy build his or using a drill press at work with the boss’s permission after hours?

Keep in mind that the GCA and NFA already indicate and the ATF has reaffirmed that you may not sell a firearm you make to anyone, ever, and may only pass it on to a family member or surrender it to the government upon your death.

Here are some other questions to consider…

Do I have to fill out any forms or pay to get a tax stamp? This one is a bit trickier. If you are building some type of modified firearm that does not fit the current legal definition of a pistol, rifle, or shotgun, you might have to. Things like short-barreled rifles, handguns with shoulder stocks, fully automatic firearms of any style, sawed-off shotguns, or anything outside the current restriction may have to be registered as an NFA item. See for the restriction list. You can usually avoid unwanted scrutiny by sticking to the basics and making sure that what you build looks a lot like every AR-15 or 1911 that can be purchased commercially. Also if you make sure it does not have a restricted modification like a suppressor, shortened stock, et cetera, you will generally be on solid ground.

Do I have to mark it or serialize it?

No, but marking it is encouraged by the ATF so they can help identify it if it is lost or stolen. Many people think marking it is a euphemism for having a means to track it. I would mark mine someplace unique and discreet in case it does get lost or stolen.

Is there is a particular part that is actually considered the “firearm”? Yes, and it varies. On a commercial firearm that component is usually either the upper or lower receiver, because that is what must be serialized and tracked through the supply and distribution chain using the serial number assigned by the manufacturer. On the three platforms discussed here, it is the body of the lower receiver or pistol frame that is serialized and recorded. On some firearms, it is actually the upper receiver because the trigger group is housed there.

What is an ATF Determination Letter?

This seems pretty important in my opinion, but use your own judgment. If a manufacturer wants to make an 80% lower receiver available and stay in the good graces of the ATF, they have typically submitted a sample and description of their product to the ATF Firearms Technology Branch, who will review the sample and confirm in writing that what they are making is not a firearm. If it is found to be compliant and not a firearm, the FTB will then issue a letter indicating that only that specific configuration from that manufacturer has been evaluated is not considered a firearm and thus does not have to comply with restrictions as a firearm. This formal notification to the manufacturer is called a Determination Letter and the manufacturers who have one will freely provide it, often right on their website. Curiously, most of the manufacturers listed in this article that I surveyed do not have one specific to their company and seem to be relying instead on the ATF’s general rulings. Consider how important the letter might be to your peace of mind as you make a decision what and where to buy.

Are there any restrictions on using the firearm?

As long as it complies with the ATF-FTB’s interpretation of regulations, it generally meets the same use and handling conditions as any other commercially available firearm except that you can’t sell it to someone else.

Are there any other things to be aware of?

Maybe. For example, here is an interesting restriction that makes little sense but still exists. The first application that a serialized firearm receiver is used for can technically never be changed. In other words, if you initially buy or build an AR-15 lower receiver into an AR-15 pistol, you may never legally recycle it later to build an AR rifle and vice versa. It must always be used in a pistol. Once your receiver is used for a particular firearm configuration, it has to stay that way over its entire life. I’m not sure if it applies to your 80% completed receiver, how it could be enforced or why it even matters, but there it is.

How and where you complete your 80% receiver is critical. It is also important that you realize your 80% receiver must be built solely by you on equipment you own. Without a vote from Congress, ATF Director, B. Todd Jones, released a ruling in 2015 which makes it illegal for a business entity to rent or loan their equipment to a private individual so that person may complete an 80% receiver.  It is also prohibited for a private individual to complete an 80% receiver using a friend’s personal equipment.  Essentially, this means the only way to complete an 80% lower is working on your own equipment (jig, drill press, drill bits, or CNC machine, et cetera) and finishing it in your own home. Otherwise, the machine shop or your friend could be considered “engaged in the business” of firearm’s manufacture, and without being licensed they could be subject to legal actions. It would be very hard to prove unless you or your friend admitted it. However, law enforcement agencies frequently succeed when they choose to prosecute someone by relying heavily on the testimony of a friend or perhaps an ex-spouse. This person can often be enticed or compelled to testify against you in some way, so keep that in mind and practice good OpSec. Don’t trip yourself up with an accidental admission or social media post that could be used against you. Here is a link to the complete ruling.

How much money can I save?

This may come as a surprise but building one of the popular 80% versions of these handguns or rifles at this time may actually cost more than purchasing a serialized receiver and assembling the other components. Even though they have less manufacturing performed on them, 80% receivers are usually priced higher than their finished, serialized cousins. I expect that will change over time, but it is almost universally true as of this writing.

So why do the build?

That’s a great question. Here are reasons most people give for why they do it:

  • I can acquire deeper knowledge of the platform and how to gunsmith it.
  • I want to see if I can do it.
  • I have a love of the platform.
  • I want bragging rights / the manly-man or girly-girl factor.
  • I don’t want the government to know what I have. (BTW, to keep the lowest profile, make sure you are paying with cash, like a money order, have parts shipped to an offsite location, and don’t post it all over your social media.

In Part 3, we will detail the actual process of doing an 80% AR-15 build.