TSA agents discovered the weapon in a passenger’s luggage during screening at the Reno-Tahoe International Airport. The gun was a replica, but was loaded with five live .22-caliber bullets, the agency said.

The fact that it was inoperable didn’t matter, the TSA said. Fake guns are treated just like real ones — permitted in checked bags, but banned in carry-ons.

The gun might be the first 3-D printed firearm confiscated in the United States, TSA spokeswoman Lorie Dankers told the Associated Press.

The passenger, whose name hasn’t been released, voluntarily left the gun and ammunition at the airport and boarded his flight, the AP reported. He wasn’t arrested or issued a citation, but could still face a civil fine of as much as $7,500, Dankers said.

Guns and other weapons manufactured with 3-D printers pose a major security risk in air travel. For one, they’re typically made of plastic and resin, allowing them to easily slip through airport metal detectors. They can also be broken down into their component parts, enabling carriers to store them in different places and reassemble them later.

The godfather of 3-D guns was designed by Cody Wilson, a 25-year-old law student at the University of Texas, who uploaded the blueprints for it on his website, Defense Distributed.

Wilson printed the gun, known as the Liberator, on an $8,000 printer and field tested it in May 2013. The State Department quickly ordered Wilson to remove the blueprints, and he complied, but not before they’d been downloaded some 100,000 times.

The same month, reporters from the Daily Mail printed their own version of the Liberator and snuck it through security onto a crowded Eurostar train without setting off any alarms.

“Two reporters passed completely unchallenged through strict airport-style security to carry the gun on to a London to Paris service in the weekend rush-hour, alongside hundreds of unsuspecting travelers,” the Daily Mail reported, saying the journalists had exposed a “massive international security risk.”

The TSA has been criticized for security lapses as well. The agency came under fire last year when an internal investigation revealed that teams of inspectors were able to smuggle a range of banned items — including mock explosives and weapons — through airport security in nearly 70 tests conducted around the country. The acting TSA director resigned in response.

Still, in 2015, the TSA confiscated a record 2,653 firearms in carry-on bags. By contrast, the agency found just 660 in passenger luggage in 2005. And earlier this year, TSA set another record by confiscating 73 guns in a week.

The TSA’s Instagram account, where the agency posted pictures of the seized 3-D revolver, offers an amusing — and mildly frightening — look at just how many prohibited items screeners recover on a daily basis.

Don’t worry, though: The mummified head of Jeremy Bentham is allowed in your carry-on.