Colorado lawmakers pass bill to ban 3D printing of guns after veto threat forces amendments

Seth Klamann, The Denver Post on Mar 30, 2026

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DENVER — Colorado lawmakers are poised to pass legislation prohibiting people from using 3D printers to make firearms and gun components — but only after stripping out a key provision in the face of a veto threat from Gov. Jared Polis.

As it stands, House Bill 1144 would expand on the state’s existing ban on unserialized “ghost guns” by prohibiting anyone from using a 3D printer to manufacture guns or components like large-capacity magazines and rapid-fire trigger activators. The Democratic measure passed the Senate on a party-line 23-12 vote Monday morning.

The bill now needs a procedural vote in the House before it moves to Polis for signature into law.

“The rise in 3D-printer technology has introduced a new front in our fight to prevent gun violence in the United States,” state Sen. Tom Sullivan, a Centennial Democrat, said in a statement. He’s sponsoring the bill with state Sen. Katie Wallace. “It is imperative that we act right now to shore up existing law to prevent the at-home production of ghost guns, saving countless lives before they are threatened.”

The bill passed swiftly Monday, with no discussion. But on Friday, Sullivan and Wallace proposed a late amendment to strip out a part of the bill that would have also prohibited people from selling or distributing the “digital instructions” needed to print the guns and components.

“Regulating the distribution of digital instructions of 3D printing of firearms was a key part of this legislation,” Sullivan said during Senate debate Friday. “After months of open discussion about what this legislation set out to do with interested parties ... the Senate sponsors were told that without an amendment removing that regulation, the governor would veto the bill.”

In a statement, Polis’ office said that the governor’s staff had raised concerns about the digital instructions early in the legislative process. Polis spokesman Eric Maruyama did not directly respond to the criticism from lawmakers but said the legislation “closes a dangerous loophole.”

“The governor appreciates the sponsors’ and advocates’ hard work on this important issue,” Maruyama wrote, “and is supportive of efforts to ensure our Second Amendment rights are protected, promote responsible gun ownership and keep our communities safe from illegal firearms, including ghost guns, and senseless gun violence.”

HB-1144 is not the first time Polis has demanded amendments that have weakened Democrat-led gun control bills.

Last year, his office opposed a measure that would have significantly limited the sale of semiautomatic rifles. His opposition prompted scrambling to change the bill, ultimately turning the restriction into a training requirement, under which guns of that type could still be sold to people who completed certain educational courses.

During debate Friday, both Sullivan and Wallace indicated that they planned to resurrect the removed part of the bill in the coming years — after Polis’ term has expired and a new governor occupies his office on the first floor of the Capitol in early 2027.

“Since a positive debate would’ve only ended in a veto by one, we have decided to accept the cleanup and, next year, come back with a new administration in place,” Sullivan said.

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