Back in 2015 I started working on a project for producing a kit for home builders to make their own AR-15 lower receivers. I called the idea Silver, and it was really going to be a sort of hobby thing for me, separate from my day job. Life got in the way and I never did anything with it, until this week when I sent out to have glass filled nylon SLAs (3D printed models) of the parts made. I’ll have more on that project in a few days after I receive and assemble the parts.

Since I started working on Silver, home-made firearms have been very much in the news, not because they are causing a lot of problems, but because a lot of politicians want something to talk about besides the difficult problems they were elected to solve, because solving difficult problems is hard. So they have a new word for home-made firearms: they call them “Ghost Guns.” Get it? No, I don’t either. But politicians like to put out a lot of press releases and hold press conferences about “Ghost Guns,” and the press, generally not being very thoughtful or intelligent, well, they just east this stuff up. Ghost Guns!

Americans, probably uniquely, are legally permitted to manufacture firearms at home, and there are a hell of a lot of Americans doing it. They mostly do it for fun, as a hobby, in the same way that home woodworkers will build furniture that they could easily purchase at a fine furniture store. That’s kind of an American thing, actually, always has been.

There are several different categories of home build. First you have the scratch builds, basically shade-tree engineers coming up with new and novel firearms designs and making them from materials you might find at the scrap yard. These aren’t as common as the other sorts of builds, because working out new firearms designs is hard (not as hard as solving complicated social problems, but still harder than a lot of other things you can do with your time). It takes a special creative and mechanical talent to successfully scratch build firearms (and, let’s face it, a degree of bravery, or maybe foolhardiness). Also, if your firearms design is too novel, it can run afoul of state laws prohibiting “zip guns.”

Next you have the kit builders. This is a much bigger hobby in the US, and is a direct result of the 1968 Gun Control Act and later clarifications by the ATF that prohibited the importation of “non-sporting” firearms into the US. Now, military designs of all types have always been of keen interest to American firearms enthusiasts, but the “non-sporting” clause basically cut off the supply of many foreign military surplus platforms. So instead a new industry emerged where importers would buy up lots of surplus rifles from various governments; “demil” them by literally chopping them up with a saw or acetylene torch; then import them into the US for sale to hobbyists as parts kits. After that it was up to the hobbyist to make a new receiver (usually out of steel) and put the parts back together.

Then there is the so-called “80%” market. This came about because of the modularity of the AR-15 pattern rifle (which I will get into below), and the opportunity for non-FFL manufacturers to produce “80% complete” AR-15 lower receivers that the hobbyists could finish making at home with a drill press and/or a router. The 80% business has spread to many other platforms, including some handgun designs.

Finally, there is the vast universe of the homemade AR-15 lower receiver itself. As I mentioned, the AR-15 pattern rifle is extremely modular, with all its components available from any of hundreds of manufacturers and suppliers, and all these parts can be fitted together more or less like LEGO to build rifles. All the parts except the receiver, including the bolt assemblies and barrels, can be purchased without paperwork by anyone, from anywhere, at least within the US (ITAR regulates and restricts the international commerce of gun parts). So anyone with a credit card can buy everything he needs to build an operational AR-15 rifle without leaving his couch, except the receiver, which has a serial number and which (when buying a new one) requires a background check and a Form 4473.

So lots of guys like to come up with new ways to make an AR-15 lower receiver, because once you have the receiver you can get the rest from Brownells or MidwayUSA.

I have long kept a modest supply of AR-15 lower receivers (or “lowers”) on hand so that in case I want to build a rifle project I don’t have to start by visiting a gun store and buying a lower receiver, with all the necessary paperwork; I just grab one out of this bin:

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These have all been purchased over the years from gun stores, with the background checks and Form 4473s, etc.

Over the last couple years my cache of lowers has been depleted by projects, including rifles I built for two of my employees. A local gun store had a sale where they were selling Anderson lowers for $39 each (regular price $60). I bought four $39 lower receivers, and brought my supply back up to 12 proper AR-15 lowers (plus two clear plastic lowers I might someday build into .22 rifles; a weird skeleton lower I’ll probably end up selling; and a pair of lowers that don’t accept magazines that I bought during the California AR-15 interregnum of 2000-2005 and which are now museum pieces).

Anyway, the AR-15 lower receiver design is essentially in the public domain, and the dimensions, including 3D CAD files, freely available online. So there are a lot of hobbyists making lowers from lots of different materials, just because. I have seen lowers produced at home using the following techniques:

Finally, there is my own Silver design, using aluminum extrusions.

As you can see from the photos and videos at the links above, most of these home-built AR-15s are really rather ugly. The steel and wooden ones especially are a lot of work to produce. People aren’t making these just because they need or want an AR-15 rifle; they are doing it for the fun and the challenge.

Despite the rantings of grandstanding politicians, these “Ghost Guns” are rarely being produced for nefarious purposes. There have indeed been occasions when prohibited felons made their own firearms and used them in crimes. But generally if you are a prohibited person and aren’t worried about following the law anyway, you will probably procure a firearm either by stealing one; buying a stolen gun on the back market; or buying a legitimate gun in a face-to-face unpapered transaction in any of the 40-45 out of 50 American states where this is legal and common (the dreaded “First Amendment Loophole”). You aren’t going to go through all the hassle of making a “Ghost Gun” out of aluminum or plastic; that is strictly for hobbyists and enthusiasts.