Colorado lawmakers moved closer to banning 3D printed firearms and more tightly regulating the sale of gun barrels Monday morning.
Legislators in the House voted 40-25 to pass , the 3D printing bill. At roughly the same time, the state Senate voted 19-16 to advance , which would require firearm barrels to be sold or transferred only by a federally licensed firearm dealer. Each bill will now switch to the opposite chamber and restart the process; each are likely to clear their next several votes and move to Gov. Jared Polis.
Both measures were exclusively backed by Democrats, who hold nearly 2-to-1 majorities in both chambers.
HB-1144 would prohibit the manufacturing of 3D printed firearms and gun components, including large-capacity magazines, rapid-fire devices and unfinished frames or receivers. It also bans the selling or distribution of instruction manuals that could be used to produce the devices. Anyone who violates the law would face a misdemeanor charge on a first offense; subsequent violations would result in a felony charge. The bill does not apply to licensed gun manufacturers or accredited gunsmithing programs.
“The ability to access a 3D printed firearm and commit an act that nine times out of 10 is fatal is unique, and (is) something we can speak to. This bill seeks to do that,” Rep. Andy Boeseneker, a Fort Collins Democrat, said during debate Monday. He’s sponsoring the bill with Rep. Lindsay Gilchrist.
Lawmakers previously banned the possession of so-called ghost guns, which are firearms without serial numbers. Between August 2024 and December 2025, the Colorado Bureau of Investigations seized 89 ghost guns — or “personal manufactured firearms” — spokesman Rob Low said in an email last month.
Republicans argued that the bill was unconstitutional and violated the Second Amendment. Rep. Rebecca Keltie, of Colorado Springs, accused one of the bill’s sponsors of legislating because of his “emotions” related to guns. The bill is co-sponsored by Sen. Tom Sullivan, whose son was killed in the 2012 Aurora theater shooting.
Later Monday, the Senate comfortably passed SB-43 after more Republican opposition. In addition to regulating who can sell gun barrels, the bill also requires that sales are made in person and that records about each sale be kept for five years.
Sullivan, a Centennial Democrat who’s also sponsoring the barrel bill, said the proposal is a further attempt to crack down on so-called ghost guns, or unregistered firearms.
“This is not an attempt to put anyone out of business or register anything so that at a later date someone will come to confiscate those items,” Sullivan said during floor debate on Friday, ahead of Monday’s final vote. “Times are changing … (and) the ghost gun has become a new problem for law enforcement.”
Republicans, who opposed the bill, launched a lengthy debate about the legislation Monday morning, characterizing it as an infringement on Second Amendment rights and law-abiding gun owners.
“Here we have a piece of legislation that masquerades as a public safety measure but in reality strikes at the very heart of our constitutional liberties,” Sen. Lynda Zamora Wilson, a Republican who lives at the Air Force Academy, said.
The votes kicked off a day of gun-related hearings and debates in the Capitol, where gun control measures have become increasingly common as Democratic lawmakers have settled into comfortable majorities over their Republican colleagues. Elsewhere Monday, a House committee was set to debate bills to and to expand take a person’s firearms away. A Republican-backed measure to was also set for its initial hearing.
