Everyone knows about 3-D printed guns. Now a hobbyist from Tennessee has created 3-D printed shotgun slugs. Then he sent them to his friend, who took the slugs and blasted away.

In a video posted to internet this week, Jeff Heeszel, a 48-year-old industrial technician from Visalia, California, is seen firing three 3-D printed slugs from a Mossberg 590 shotgun. The first two slugs both hit their targets at a range of about 25 to 30 feet. The first slug penetrated a dart board. "It went right through that," Heeszel tells Danger Room. And then carried on to penetrate through a water jug. The second slug blasted through a 2x12 piece of pine wood, and then bored a hole in a wire reel. A third slug with a three-pointed front was then fired at much closer range at a mannequin's head, but just knocked it over.

Heeszel was surprised at the first two. "I didn't think it would go through the first piece of wood at all, much less hit anything," he says. But he also called them more of a novelty than a practical bullet. "I thought the thing was kinda lame, but I realize there's a lot of novelty with the 3-D printed gun, and I thought it was kind of timely. But overall I think they're kind of crappy little rounds," he adds.

Heeszel, who runs the popular YouTube channel Taofledermaus, isn't an anarchist or a political activist like Cody Wilson, who created the world's first fully printable gun. Heeszel's videos are more like Nickelodeon-style entertainment with firearms, with lots of slow-motion and videos of silly putty and frozen Vienna sausages being blasted out of shotguns. It's also why his friend Tony Griffy, a 50-year-old design-build contractor from Chattanooga who designed the printable slugs, chose him to shoot the things.

"I might be a redneck from Tennessee, but I love the technology," Griffy says. Griffy, who runs a YouTube account ArtisanTony – where he also shows off a printable knife and buckshot rounds – tells Danger Room he printed the slugs more for their own enjoyment. "Because a real gun shooting plastic bullets is more fun than a plastic gun shooting real bullets," he says. "You have to spend six hours printing a barrel that you're going to use one time, and it's not as much fun. It's more about the enjoyment and the sport. And if you're having to labor that much, then the enjoyment goes away."

Griffy says he printed the slugs with a Solidoodle 3 3-D printer – which retails for $800 – using ABS thermoplastic using dimensions from one of Heeszel's non-printed slugs. Griffy then created the computer-aided design files, converted them to a stereolithography format, and checked the files for inconsistencies with the 3-D printing software Netfabb. He also designed slugs in three sizes. The largest slug takes about an hour to print. The others take about 30 minutes. He also added a lead ball to each slug to give them more weight. The final step was mailing them to Heeszel, who fitted the slugs into hollowed-out – non-printed – shotgun cartridges.

It will also take hours to set up a machine to print them in a workable shape. 3-D printers print by squirting out thin layers of melted plastic, which harden and cool into a design. "The biggest problem I had was the print sticking to the bed of the printer," he says. The printer's base is heated, which causes skinny printed objects to warp when the upper layers begin to cool. He solved this, he says, by creating and painting a slurry mix to the printer bed. It took "30 to 40 hours just reading forums" to find the right mix, he adds. Then he spent hours more tinkering with the printer's settings.

The slugs are also still really lightweight. It doesn't "have a fraction of the force that a real slug would have," he says. The interior of the slug is mostly hollow, and Griffy says he'd like to modify it to make it more solid in the future, allowing it to better stand up to air resistance. (This will also make them take longer to print.) But he doesn't plan to mass-produce them, and he doesn't claim to have any political motives.

"Printers are really designed for prototyping, not production work. It's really, honestly, just for fun," he says. "I like Jeff, I love his videos, he's the one who got me into slow-motion stuff. It's all about the hobby of producing neat videos with some character. And of course I love the high-tech stuff."

As for Wilson and his 3-D printed guns? Griffy has toyed around with the 3-D printed handgun, but doesn't plan to share it himself. "They want people to think they're liberty-minded, but really they're making money off of these young people out there who just want to see a fight." He's more happy to stick with seeing just how far his printable slug will go.