What is a ghost gun?

Rolling Stone came out with an article titled "This Man Wants to Help You Print Your Own Gun" by Jack Crosbie. An attention grabbing title on a topic coming more and more into the mainstream. Overall, the article provides a pretty matter of fact representation of the topic of 3d printed firearms, one type of so-called ghost gun.

But what exactly is a ghost gun and why does it deserve a haunting name. Really the title of ghost is not meant in the scary movie and mythological sense of the word, but more the unseen sense of the word. They are ghost guns because they do not have serial numbers, a common way to trace many manufactured items from a manufacturer, to a distributor, to a retail store, and ultimately to the buyer and user. But, firearms did not always have serial numbers. A ghost gun is generally not referencing an antique firearm, even though many older un-serialized firearms still work as intended. So, the second attribute a ghost gun needs to have is a post-serialization era manufacture date. This means the firearm was made of metal or plastic (or some other material) relatively recently. This means that ghost guns cover a block of aluminum turned into an AR receiver on a CNC machine, an 80% complete pistol lower that is finished at home, or a 3d printed receiver/lower created from a file downloaded from the internet.

The United States has tons of firearms, more than one per person, so why are some people so worried about these ghost guns? Well the main worry is that a firearm produced without a serial number also means a firearm that was obtained before a background check was performed. This does mean that a person previously convicted of some kind of felony would be able to produce a functional firearm to own where they would be denied from buying a firearm in a store.

Other people focus on the ghost aspect of the firearm not being traceable through a firearm. This hovers around the same concept of keeping firearms away from people that have parts of their history that would disqualify them from obtaining a firearm, or groups of organized people. In the United States, a firearm is generally defined as the lower receiver or frame only. This means a firearm can be just this part. Not a functional firearm as it would be missing several parts needed to function like a barrel, firing pin, trigger, among many other essential parts. In the US, the firearm (lower receiver or frame), has to be serialized and documented by the manufacturer as soon as practical after becoming more than 80%. This means that if a worker managed to smuggle out a crate of serialized pistol frames and sell them to some organized crime element, these serial numbers would be able to be traced back to the manufacturer and an investigation would begin on who trafficked the pistol frames. On a smaller scale, the serial number can also be used to get a stolen firearm back to it's owner, or track a private sale, where the official ownership of the firearm would be transferred to the new owner via this serial number. This would remove culpability for the previous owner for where the firearm turns up next.

But, are they really ghosts? Are these firearms truly untraceable? As a forensic firearms examiner, I know they are still traceable, but it's much harder than entering a number in a database. National databases store images of fired cartridge cases from crime scenes that will link up to test-fires from a recovered firearm. This means if a firearm is used in California, then taken back to Las Vegas, as long as the California agency collects and processes the fired cartridge cases from its shooting scene, the recovered firearm in Las Vegas can be test-fired and traced back to its use in California. The same can be done even if the firearm ends up traveling several states away. Particularly with 3d printed firearms and related parts, studies are being done on how to trace these back to the printer that made them, scraps thrown out in the trash, or back to spools with leftover filament through physical and chemical comparison. There are also many forms of digital evidence from buying parts, downloading files, search history, social media history, and computer programs needed for 3d printing. All these parts also have to be mailed.

Does this require much more work? Certainly. It also requires much more personnel and equipment. It does demystify the ghost aspect though. A common theme in forensics, as stated by Dr. Edmond Locard, is that every contact leaves a trace. There is no difference here, with both physical, chemical, and digital traces.

It will be interesting to see if, particularly in the US, all the efforts to ban websites and force 3d printing companies to try to install various software or hardware that will limit what people can print will stand up to legal challenges. I am particularly concerned about retroactive penalties where people who bought printers to print fidget toys to sell at farmers' markets could potentially get in legal trouble for not registering their printer or getting a certain piece of hardware with certain firmware installed, especially since this firearm design identifying technology does not even exist yet. It is very similar in concept to me as the microstamping laws of California. We already have laws and methods for tracking down people in the US who use firearms illegally. I am also not entirely convinced that a person who really wants a firearm to commit a crime will not obtain a firearm through straw purchases or other means, considering the amount of available firearms in the US. I think the focus really should be to fund the forensic labs and fund the training needed to properly investigate and gather evidence to adapt already existing methodologies to this new situation. This is obviously different in countries who do not have the same amount of firearms.

In review (for the US), a ghost gun is a modern firearm (lower receiver or frame) that was created without ever having a serial number (scratched off serial numbers do not count). It can be made from multiple types of material, generated from cutting away a block, finishing something already 80% finished, or by adding material into the proper shape. They do not have a serial number, but they are not un-traceable. The term privately made firearm is more appropriate for this reason. It's still a firearm with all the same forensic value as any other firearm, it just does not have the same easy administrative tracking as brand name manufactured firearms.