Due to life happening, I didn’t get around to writing this in nearly the timely fashion I had planned.

It’s important to remember our laws are not sane.

I just wanted to start with that, because this post is about firearms, aka “lower receivers”.

“Uh, I’ve never heard of a lower receiver. What’s that?”

Let me put on a teacher’s cap for a minute and do my best to explain.

In 1968, the wonderful minds in Congress (yes, that was a joke – it’s alright to laugh) passed the Gun Control Act of 1968. (With a name like that, you’d probably guessed it was passed in 69, which is why I specified the year. That’s just the way our government works.) It created large portions of the mess we have in gun laws today.

It made it a crime to sell a firearm to a convicted criminal, created the ugly FFL system which is required for any cross-state-lines transfer (and de facto banned mail-order firearms, save antique guns – interestingly enough, the first model AR-15s should be hitting antique status very shortly if they haven’t already), restricted firearms imports in a variety of ways, and, of relevance to this post, required all licensed manufacturers to put serial numbers on their firearms.

Staying on topic here, the last point is what’s relevant to “firearms are lower receivers.” The question on serial-numbering firearms is what is the firearm?

To which some of you are saying, “Huh?”

It’s critical to remember that firearms are like any other machine – they’re a combination of parts. Since the Industrial Revolution, firearms are manufactured with enough precision that parts are interchangeable. So, on any given firearm, you have dozens of parts which are all interchangeable and can be replaced as needed. So for the sake of the Gun Control Act of 1968, which component is the “firearm”? Is it the firing pin or hammer? Trigger? Barrel?

In general, it’s considered the weapon’s “frame” or “receiver”, which all other parts fit into. With most firearms, this is an adequate definition, but with the advent of modern sporting rifles, it gets to be ludicrous.

My brother once referred to the famous semiautomatic Ruger 10/22 as a “LEGO gun”. Aftermarket customization kits are available for Ruger 10/22s that can make them all sorts of interesting firearms, from AR clones to gatling guns. They’re easy to work with and anyone with some basic tools can manage such a conversion.

The AR line takes it a step further. They’re designed to be fully customizable from the get-go. Online tools make it easy for people to put together a virtual firearm with all the features they want, then get a parts list and order everything they need to put it together in reality.

ARs are designed to such a degree, in fact, that it actually has two receivers – an upper receiver and a lower receiver. The only part that is serial numbered and tracked by the federal government is the lower receiver. All other parts are just considered “components.”

So, now that we’re this far into our education, let’s take another peek at what the 1968 law did? It required all licensed manufacturers to put serial numbers on their firearms.

Licensed manufacturers.

Something that seems to be often missed is that anyone in the US can manufacture a firearm for themselves. (Caveats apply; basically, anything you can buy without special tax stamps you can build. You can’t build a fully automatic weapon, for example; short-barreled rifles would have to be registered with the Feds. Etc, etc, etc.) Until recently, this was a very niche crowd – people with the specialized tools and knowledge to build a reliable firearm aren’t common. Now, if these unlicensed people build a firearm for themselves (can’t be for resale), they didn’t have to put a serial number on it. It would be impossible to enforce, so the Feds wisely decided to leave it be.

But the Internet changes everything.

Now, manufacturing a lower receiver from scratch isn’t easy. It still requires specialized tools and knowledge. Buuuuuuuut, a number of manufacturers started poking at the edges of the law to find out just where the line between “legal” and “orange jumpsuit” lies.

Enter the 80% lower receiver.

BATF basically states that any receiver that is 80% or less complete is not a firearm under the 1968 law, because it’s too far from usable. So, these 80% receivers can be sold without a serial number, without filing paperwork with the federal government, and without doing background checks.

And the rest of the parts are, again, untracked.

How difficult is it to complete an 80% receiver? There’s a few different ways to go about it. The manual way is most difficult. However, CNC mills are becoming the more popular way to do it. I’ve also read plenty about “AR parties” where a group gets together and someone with the proper knowledge walks newcomers through the process.

End result, a fully-functional AR-15 that the federal government can’t track because they don’t know it exists.

And remember, this is with the technology we readily have available now. Just imagine what it’s going to be like in another twenty years.

Yes, ban “assault rifles” – it’s going to do so much good.

I’m working on part III – 3D printing. It should be fun.