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If the Instagram account for the Transportation Security Administration (TSA) tells us anything about the psyche of the United Sates, it is this: The country has a surprising interest in owning Batman-replica boomerangs; and  Americans are locked and loaded, and they often forget this fact when flying.

Last week TSA caught a near-record 68 firearms in people’s carry-on luggage—including a 3D-printed pistol. That pistol was about five-inches long, plastic, and nearly made it onboard a plane in Reno, Nevada. Luckily, it was loaded.

A photo posted by TSA (@tsa) on

I say luckily because the metal ammunition likely made it easier to detect.

People flying in the U.S. try to pack some unconventional things in their carry-on luggage. At the Raleigh-Durham International Airport this year, officers caught one passenger with an inert rocket-propelled grenade in a carry-on bag. In 2014, someone in Northern California tried to smuggle a knife wrapped in an enchilada (an act TSA described as delicious not malicious). And each day TSA stops about seven guns from making it onto airplanes. This April, the agency caught a record-number: 73 in one week. This is a common occurrence in the U.S., as the cover story in The Atlantic this month points out. Even after 15 years of pat-downs, beeping metal-detector wands, full-body scanners, and shoe removals, TSA found more than 2,500 guns in carry-on luggage in 2015, more than 80 percent of them loaded. A 3D-printed gun, however, is new.

It’s not illegal to fly with a firearm. Legally, when those 2,500 gun owners arrived at the airport last year, they should have declared their firearm to airport attendants during check-in—a process that involves holding the gun, unboxed, in the airport to show the attendant it’s not loaded. The gun then flies with the other checked-luggage, safely in the plane’s cargo hold.

But carrying a firearm on a plane is a no-no. More than that, it’s illegal to take anything that even looks like a gun or weapon on a plane. This includes any type of replica firearm, ammunition, or explosive. No Batman boomerangs. No bath salts (not the drug) shaped like bottles of TNT, even if they were wedding mementos for a bride and groom whose names both began with “T.” And certainly no plastic guns.

Absentmindedness, the TSA points out in its blog, is often to blame for why officers catch so many firearms at security checkpoints. In many gun-friendly states, carrying firearms is simply a way of life. A Guns & Ammo article about how to properly fly with a firearm even began with the words, “If you’re like many of us, carrying a firearm doesn’t cease when traveling away from home.”

But gun owners are either growing more forgetful, or despite its 95 percent fail rate in detecting weapons, TSA is actually catching more guns at security checkpoints. From 2014 to 2015, TSA saw a 20 percent increase in firearms in carry-on luggage. That figure, seemingly, does not include replica guns, which is how the TSA categorized the 3D-printed pistol.  

A photo posted by TSA (@tsa) on

The gun TSA caught last week was smaller than the palm of a hand. It held five .22-caliber bullets, ammo typically used to shoot small game, like rabbits. It also looked identical to a derringer, a weapon that became synonymous with Western card sharks because it could easily be concealed, and was famously used by John Wilkes Booth to shoot Abraham Lincoln.

The TSA called the 3D-printed gun a replica. It’s unclear if that’s because the gun is made of plastic or because it lacked a firing pin, which would make it unable to shoot (though, in most cases, a firing pin can easily be added). Either way, some people in the 3D-printed gun movement are unhappy.

Three years ago, Cody Wilson, 25, a law student at the University of Texas, told the world he would print a gun. Then he did it. He called it the Liberator and he shared the design online, essentially making it available to anyone with a 3D-printer. The 3D-printing industry has tried to self-regulate by seizing machines that landed in the hands of companies devoted to printing guns, like Defense Distributed, a company that has 3D-printed high-capacity magazines for assault rifles like the AR-15s and AK47s.

Wilson’s design, the Liberator, is widely recognizable. As are many of the designs passed around in forums, and between gun-printing enthusiasts. But the design found by TSA is relatively unknown, according to an article in 3D Printing Industry.

Unfortunately, the TSA hasn’t released too much information about the gun that was found. It could be an ambitious plan by an amateur that was destined to blow up in their hand the first time they fitted a pin. It could also be a prototype for a company that intended to produce the gun legally. We cannot tell for sure.

All we really know is that 3D printed guns are in the news again and that is not good for any of us.

The Undetectable Firearms Modernization Act outlaws the creation of a firearm that a walk-through metal detector can’t spot. This is why, in order to stay within the law, 3D-printed gun designers add a metal component to their weapons, typically the firing pin. It wasn’t clear if the gun TSA caught had that required metal component, aside from the five bullets in the cylinder, which likely made it a lot easier to detect because ammo is metal (brass casings and lead bullets).

Since the 9/11 attacks, the government has invested billions in the TSA. Last year, when the department’s budget was $7.2 billion, the agency’s head lost his job after the department failed to catch undercover Homeland Security agents smuggling weapons or explosives 67 out 70 times.

Each week, TSA posts photos to its Instagram of the weapons it confiscates. Luckily, agents caught the knife inside the enchilada, and they caught the loaded 3D-printed pistol. But if TSA’s track record is correct, it means that of the 68 guns it caught this week, there might be many, many more it didn’t catch—metal, or plastic.

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