Apparently there seems to be a wild consensus about guns that don’t have enough metal in them and sneak past metal detectors. Yes, no, in between. It seems all the fictional stories I’ve seen with such guns seem to be stretching plausibility or have enough sci fi or magic in it to make someone gloss over accuracy for cool mechanic. But what is it really?
It’s a myth. Or at least, it used to be, and now that it’s less of one, it may not matter anymore.
The major origin for this seems to have been the early Glocks. The Glock was not the first handgun on the market with a polymer frame, but it was the first to try to make that a serious selling point.
This lead to panicked speculation that the Glock could be taken through metal detectors. You can even see the extreme version of this in Die Hard 2 (1990), where the scriptwriters had it in their head that the Glock was manufactured from “porcelain,” and was invisible to metal detectors. The entire, “Glock 7” dialog is downright painful for anyone with passing familiarity with firearms.
It’s worth noting that the polymer frame does make the Glock considerably lighter than a steel framed pistol of that size. The other major solution that was being used were aluminum frame pistols, (like the SIG P226.) We’ve said it before, but weight is an important consideration for any weapon, and use of lighter materials like aluminum and polymers can be beneficial.
Also, while I’m not an expert on polymers, it’s worth noting that the Glock, technically, isn’t plastic. It’s a high-impact polymer that’s more closely related to nylon. Now, plenty of people (myself included) do sometimes use polymer and plastic interchangeably, but that’s not accurate. All plastics are polymers, but there are many polymers (both naturally occurring and synthetic) which are not plastics.
By weight, the Glock is over 80% steel. That’s a little misleading, because the polymer components are quite light, and the steel isn’t, but when you remember that the foil in a pack of cigarettes, or even your belt buckle can set off a metal detector, it illustrates how misunderstood the early polymer frame pistols really were.
For the time, the steel components in a Glock were necessary. You couldn’t replace them with polymer components and get a firearm that performed to the desired specifications. In particular, trying to use a polymer barrel would have resulted in a gun that would explode when fired. Even today, creating a polymer barrel is an engineering challenge. Creating one that will survive regular use is (probably) not possible with current technology.
Now, what really does exist are polymer combat knives. These will hold an edge, can go through a metal detector, and you can buy them for less than 20USD. (Less than half of that if you shop around.) Which part of why you probably haven’t been through a metal detector in the last decade.
As a technology, metal detectors are on the way out. Like many pieces of security technology, the metal detector came with a shelf life. They were designed to prevent people bringing contemporary weapons into secured areas, which lead to people developing weapons that could circumvent them.
In the last 20 years, there’s been a steady shift towards full body scanner technology. The big two are X-Ray scanners (both backscatter and direct transmission), and Millimeter Wave Scanners. These will detect polymer weapons.
Supplementing them is the old standard of a pat down search. It doesn’t matter if you have a space age gun that can go through a metal detector when someone can find it with the back of their hand while checking you for weapons.
Similarly, even if you did have a space age plastic gun, bullets and shell casings are still metal. They’ll still set off a metal detector, and they’d still show up under backscatter.
This also leads to the Defense Distributed Liberator. The Liberator is a 3d printed, single shot, firearm, which takes it’s name from FP-45 Liberator.
So, some quick history: The FP-45 Liberator was a single shot firearm designed by the US Military in World War II. These were crudely stamped steel pistols. They were intended to be air dropped into occupied France, where members of the French Resistance could capture them. The entire goal was to provide Resistance members with a weapon that could be used to kill an enemy and take theirs. To best of my knowledge, actual deployment of the FP-45 was extremely limited, and the only confirmed use of one was to assassinate a German police officer.
The Defense Distributed Liberator was designed around the idea that if you had access to a 3D printer, you could make a gun. The gun’s existence was more of a political statement than an actual tool for rebellion or defense. The end result is a firearm that could, theoretically, get through a metal detector (though the ammunition can’t), but it is also only as reliable as the material you print it out of.
When the AFT was testing the Defense Distributed Liberator, they used a variety of materials. Their tests with ABS-M30. resulted in a gun that was successfully test fired eight times. At which point, they declared the Liberator a lethal weapon. Some of their other tests resulted in catastrophic failures on the first shot.
While considering the Liberator a lethal weapon entirely valid, firearms usually measure their lifespan in tens of thousands of rounds fired. Breaking in a gun frequently involves putting a thousand rounds down range. Right now, it’s not possible to make a polymer barrel that will stand up to that level of stress while also delivering an acceptable lifespan. A gun is not useful if it explodes in your hand before you can empty a magazine, and that’s the problem with polymer internals.
So, the short answer is, even though there are examples, the plastic gun is mostly a myth. Even if you have a plastic gun, the ammunition would still set off the metal detector. Even if you could get around that, the gun would still be found with a simple pat down, and would show up in Millimeter Wave or Backscatter scanner.
The myth is real only in the sense that people believed it. It started with a misunderstanding about the Glock’s engineering by people who didn’t understand guns (and weren’t willing to listen to those who did understand the engineering), and it all went downhill from there.