Thingiverse is an online community for 3D printers to share ideas and blueprints of various objects people can create at home. It’s a neat place to learn more about getting creative with your 3D printer… that is until Thingiverse user HaveBlue declared that he has completed a project that could print a working semi-automatic rifle capable of firing at least 200 rounds without fail.

According to Popular Science, HaveBlue 3D-printed a 0.22 caliber pistol which he adapted from an AR-15 rifle model. The item only cost him $30 worth of ABS plastic to complete. Though the prototype works, HaveBlue states that more modifications are still necessary thanks to existing feed and extraction issues. But the fact that anyone could download the blueprint and attempt to create their own weapon at home makes us more than a little nervous.

“Everything ran just as it should, magazine after magazine,” HaveBlue describes in a blog post of his printed rifle. “To be honest, it was acting more reliably than a number of other .22 pistols I’ve shot.”

Of course, anxiety aside, this is a rather remarkable breakthrough for 3D printing. The ability to create functioning weapons at a lower cost could mean more economical weapon production in the future — it’s just a matter of making sure the blueprint do not fall in the wrong hands. Although HaveBlue’s design is widely available on Thingiverse (at least for the time being), the site did post a blog back last October asking users whether they feel comfortable having weapon designs available. Indeed, tons of weapons can be 3D-printed other than guns, including claw knuckles, Shurikens, and an anime-style dagger knife. Since HaveBlue’s design remains on the site, perhaps Thingiverse has yet to modify the Terms of Service. Pop Sci is reporting that the site has decided to not only discourage weapon design posts but ban them entirely, so we could see the changes take place very soon.

CORRECTIONS: The AR-15 model was not entirely printed with a 3D printer, only a piece of the material was created with plastic (as shown in the second photo). Only the lower receiver was printed by HaveBlue, not the pistol itself. I regret the error of insinuating a fully operational gun could be wholly produced from home. I must note, however, from the words of HaveBlue himself:

“Being able to make a firearm at home is nothing new – in fact, folding a receiver for an AK-47 is a very simple project that requires nothing more than hand tools. The process of 3D printing a receiver is simply using a different type of machine than in the past, nothing more. Just as with a firearm, the responsibility for the machine’s usage lies with the operator, not the device itself.”