Gov. Jared Polis has signed the most significant gun bill of the 2025 legislation, which will require individuals to take a safety training course to be eligible to buy or sell semiautomatic rifles, shotguns, or handguns with detachable magazines.

Senate Bill 003, sponsored by Sens. Tom Sullivan, D-Commerce City, Julie Gonzales, D-Denver, and Reps. Andrew Boesenecker, D-Fort Collins, and Meg Froelich, D-Englewood, has undergone significant changes since its introduction in January. Initially, there was an outright ban on semiautomatic weapons with detachable magazines. Still, the bill was amended to allow for the purchase of guns if an individual completes safety training through Colorado Parks and Wildlife.

“This legislation builds on our commitment to improve public safety, reduce gun violence, and uphold our freedoms,” said Polis. He said he was working with CPW to ensure that firearm training costs no more than $200 and that scholarships are available to low-income applicants.

Sullivan, whose son Alex was killed in the 2012 Aurora movie theater shooting and has been one of the legislature’s most outspoken advocates for gun safety, attended the bill signing with his wife Terry, daughter Megan, and granddaughter Molly.

“We’ve moved quite a distance from where the bill started and we’ve gotten to a place where we all felt a little bit of pain, but we are pleased with where it finally landed,” he said. “With the people in this room and legislators who have had the courage to stand up to our opposition, we have been able to add to the safety of each and every Coloradan, especially when it comes to gun violence. There is more to do, and I will always be at least that one who will stand up and be heard when it comes to taking action against the public health crisis that is gun violence.”

Several groups support the bill, including Moms Demand Action and Vet Voice Foundation, a progressive organization dedicated to veterans’ issues.

Harrison Tarter, an Army veteran who served in Afghanistan with the 10th Mountain Division, said veterans’ voices were crucial to the passage of the bill due to their extensive knowledge of firearms.

“There’s a big contingency of veterans that served that know these weapons and want folks to be able to make common-sense laws without being shouted down by people saying, ‘you don’t know what you’re talking about’ or that this is an emotional argument,” he said. “This state has a history of horrible mass shootings, and I think the legislature and the Governor are doing a good job of saying, hey, if we can pass a common-sense law that increases the chances that a horrible shooting won’t take place, why would we not do that?”

Opponents of Senate Bill 003 have made it clear they plan to file a lawsuit questioning the measure’s constitutionality as soon as possible. They argue that it violates the Second Amendment and creates an additional barrier for law-abiding gun owners. The courts have upheld legal challenges to similar measures in other states.

“Gun rights are civil rights,” Minority Leader Ty Winter, R-Trinidad, said during a House floor debate on the bill. He expressed concern with the fees associated with obtaining a permit, which he likened to “putting up a paywall in front of my Second Amendment rights.”

To reduce gun violence, he said, we need to be looking at the root causes, like mental illness, not taking away people’s guns.

Winter was also concerned about the state’s sheriffs’ opposition to the bill, which he said was “shoved down their throats.”

“My constituents sent me here to fight for the Second Amendment, and they made it very clear where they stand on this,” he said.