When the first working gun was 3-D printed in the United States, the government responded not through the Bureau of Alcohol, Tobacco, and Firearms, but instead through the State Department. Guns, it turns out, aren't terribly hard to get in the United States, so a 3-D printed gun doesn't radically change gun access here. In countries with stricter gun control laws, though, printing a gun is a new risk. This week, Japan sentenced 28-year-old Yoshitomo Imura to two years in prison for printing guns and instructing others on how to print them.
Imura printed a six-shot revolver known as the ZigZag. It fires .38 caliber bullets, same as those used in Defense Distributed's original 3-D printed Liberator pistol. While the majority of the gun is printed plastic, it still has a few non-printed parts. Notably, these are pins, screws, a spring, and several rubber bands. Here's a video of someone assembling a printed ZigZag revolver: