Democrats in the Colorado legislature are adding to their slate of proposals this year to tighten the state’s gun regulations with measures that would further crack down on 3D printed firearms and impose tougher rules on gun dealers.
House Bill 1144 would add to Colorado’s restrictions on ghost guns, unserialized firearms that are often assembled at home using 3D printed parts or do-it-yourself kits. They allow people to bypass background checks and are virtually untraceable.
This story was produced as part of the Colorado Capitol News Alliance. It first appeared at kunc.org.
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 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, like frames or receivers, the central section of a gun that includes the firing and trigger mechanisms.
This year’s measure, House Bill 1144, would go further by expanding on Colorado’s prohibitions on 3D printed firearm parts by blocking the manufacture of any firearm using 3D printers or similar devices, including computer-controlled milling machines that carve precise parts from material.
The legislation would also make it illegal to manufacture large-capacity ammunition magazines and devices that increase a gun’s rate of fire. Possessing those is already illegal in Colorado.
“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 3D printer,” said state Rep. Lindsay Gilchrist of Denver, a sponsor of the bill.
Other sponsors of the bill are state Rep. Andrew Boesenecker, D-Fort Collins, and Democratic state Sens. Tom Sullivan of Centennial and Katie Wallace of Longmont.
The measure would also ban the possession of the digital code or instructions used to program a 3D printer or other machines to produce a firearm or firearm part — if the person in possession of those items 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 offense, punishable by jail time. Second or subsequent offenses would be Class 5 felonies, punishable by prison.
The bill includes a carve-out for federally-licensed firearm manufacturers, who would still be allowed to 3D print guns and parts. It would also allow people to possess the digital code or instructions to 3D print firearms if they intend to distribute them through 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. The bill 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.
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 require dealers to secure firearms, 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.
House Bill 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.
State Rep. Emily Sirota, D-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 all of Democrats’ gun-regulation efforts, including the mew permitting and ghost gun bills.
State 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.” She said lawmakers should focus 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, which would expand Colorado’s red flag law. The measure was approved by the Senate on Tuesday and is awaiting its first committee hearing in the House.
This story was produced by the Capitol News Alliance, a collaboration between KUNC News, Colorado Public Radio, Rocky Mountain PBS and The Colorado Sun, and shared with Rocky Mountain Community Radio and other news organizations across the state. Funding for the Alliance is provided in part by the Corporation for Public Broadcasting.