Colorado Gov. Jared Polis signed House Bill 1144 into law on May 4, making it illegal to manufacture or produce firearms and firearm components using 3D printers. The law takes effect July 1, 2026.The legislation expands on Colorado's existing ban on firearms without serial numbers, the state's prior attempt to address so-called ghost guns. HB 1144 defines 3D printing broadly to include both additive manufacturing (what most people think of as 3D printing) and subtractive manufacturing like CNC machining, covering a wide range of home-built firearm production methods.The version Polis signed is significantly narrower than what was originally proposed. Early drafts of the bill included a prohibition on distributing digital instruction files and code related to firearm components. That provision was stripped from the bill in late March after Polis signaled he would veto the legislation if it restricted the distribution of information. The governor's office has historically been sensitive to First Amendment concerns in gun legislation, having previously expressed reservations about bills that could be read as restricting speech rather than conduct.What remains is a straightforward ban on making guns at home with computer-controlled manufacturing tools. If you 3D print a frame, receiver, or any firearm component in Colorado after July 1, you're breaking the law.The NRA-ILA opposed the bill, arguing it criminalizes a lawful method of personal firearms manufacturing that has existed in various forms for decades. Everytown for Gun Safety praised the signing, calling it a "step forward on tackling the spread of 3D-printed guns."For Colorado residents who build their own firearms, the practical impact is substantial. Home gunsmithing with a 3D printer or desktop CNC machine, which had been perfectly legal, will be criminalized in under two months. The law does not appear to distinguish between complete firearms and individual components, meaning even printing a replacement grip or magazine body could theoretically fall under the ban.