Colorado Democrats are adding to their slate of proposals this year to tighten the state’s gun regulations with measures that would crack down on 3-D printed firearms and require a state permit for transferring a gun to another person.
One of the bills would add to Colorado’s restrictions on ghost guns, or firearms that can be assembled at home using 3-D printed parts or do-it-yourself kits. They allow people to bypass background checks and do not have serial numbers, making them virtually untraceable.
Federal data show ghost guns are increasingly turning up at crime scenes. Recoveries of the weapons surged nearly 1,600% between 2017 and 2023, according to a 2025 report from the Bureau of Alcohol, Tobacco, Firearms and Explosives. Law enforcement recovered more than 90,000 ghost guns nationwide during that period.
Ghost guns have also been involved in high-profile shootings in Colorado, including the 2022 mass shooting at LGBTQ nightclub Club Q in Colorado Springs and the 2023 shooting at East High School. Lawmakers passed a law regulating the weapons in 2023 that banned the possession and sale of unserialized guns and the manufacture of certain unserialized gun parts.
This year’s measure, House Bill 1144, would go further by expanding on Colorado’s prohibitions on 3-D printed firearm parts. The 2023 law made it illegal to manufacture frames or receivers, the central section of a gun that includes the firing and trigger mechanisms.
HB-1144 would block the manufacture of any firearm using 3-D printers or similar devices, including computer-controlled milling machines that carve precise parts from material. It would also make it illegal to manufacture large-capacity ammunition magazines and devices that increase a gun’s rate of fire.
“All the protections that come with the process of owning a gun are gone if you have a random person printing a firearm through a 3-D printer,” said Rep. Lindsay Gilchrist of Denver, a sponsor of the bill.
Other sponsors of the bill are Rep. Andrew Boesenecker of Fort Collins, who also sponsored the 2023 law, and state Sens. Tom Sullivan of Aurora and Katie Wallace of Longmont.
The measure would also ban the possession of the digital code or instructions used to program a 3-D printer or other machines to produce a firearm or firearm part, if the person in possession intends to use them to manufacture a gun or gun part. It would also make it illegal to distribute the code or instructions to anyone who is not a properly licensed gun maker.
Violations of the bill would be a Class 1 misdemeanor on a first offence. Second or subsequent offences would be Class 5 felonies.
The bill includes a carve-out for federally-licensed firearm manufacturers, who would still be allowed to 3-D print guns and parts. It would also allow people to possess the digital code or instructions to 3-D print firearms if they intend to distribute them with a licensed gun manufacturer.
Gilchrist said the bill was crafted in parallel to Senate Bill 43, another measure from Democrats this year intended to curb online gun barrel sales. SB-43 would require that barrels be sold or transferred in person by a licensed dealer, that they are only sold to buyers who are 18 or older who can legally own a firearm, and that sellers keep records for at least five years.
According to the sponsors of SB-43, although some ghost gun parts can be made of plastic, barrels are typically made out of metal to withstand the intense heat generated when a bullet is fired.
Another newly-introduced measure, House Bill 1126, would tighten state oversight of firearms dealers by requiring that a state permit be needed not only to sell firearms, but to transfer them to another person.
The bill would extend training requirements to individuals who have the power to direct or manage a dealer’s policies, as well as to independent contractors who handle firearms or process transfers on a dealer’s behalf.
Dealers would be required to secure firearms and large-capacity magazines, install security alarms and surveillance systems, and report stolen or lost firearms to the state within 72 hours. Gun stores would also need specified security features like metal bars or security screens on exterior doors and windows.
HB-1126 would also expand record-keeping requirements to cover most firearm transactions, not just handguns. The Colorado Department of Revenue would additionally have the authority to fine dealers up to $100,000 for repeat violations of certain requirements.
Rep. Emily Sirota of Denver, one of the bill’s sponsors, said the legislation will “keep our communities safe and strengthen in-store display and security requirements that prevent firearm theft. The bill would expand opportunities for firearm dealers to comply with state law without compromising Coloradans’ safety.”
Republicans oppose Democrats’ gun-regulation efforts, including the permitting measure and the ghost gun bill.
Rep. Ava Flanell of Colorado Springs, a former firearms instructor, said she is concerned the bills would infringe on Coloradans’ constitutional rights, calling them “heavy-handed,” and that the focus should instead be on improving public safety through other means.
“They will make it harder for responsible citizens to exercise their rights,” Flanell said in a statement. “Republicans support public safety by holding criminals accountable, keeping violent offenders off the streets, and making sure Coloradans have access to the tools and protected rights for self-defense.”
The Colorado State Shooting Association, the state’s official National Rifle Association group, also opposes the measures.
The legislature is also considering Senate Bill 4 this year, a proposal to expand Colorado’s red flag law, which was approved by the Senate on Tuesday and is awaiting its first committee hearing in the House.
All four of the gun regulation bills introduced so far are part of a broader push by Democrats over the last several years to tighten gun regulations as a way to curb gun violence.
Last year, Democrats in the legislature passed some of the strictest gun-ownership rules in the country, including limits on firearms that use detachable magazines, with those rules set to take effect later this year.
