The legislation also bans the purchase and sale of devices that enable guns to be fired rapidly, including bump stocks.

"For folks who haven't had any gun safety training, it's very important that they get that, and this bill will make sure that people will get that education on how to operate the weapons safely and—just as important—how to store them safely," Polis said at a press conference on Thursday.

Senate Bill 25-003, the legislation, is set to take effect on Aug. 1, 2026.

Under the law, people cannot buy semiautomatic rifles or semiautomatic shotguns with detachable magazines unless they've completed hunter education training offered by the Colorado Parks and Wildlife and a "basic firearms safety course."

Local sheriffs must sign off on completion of the course, with applicants also undergoing a background check and vowing not to violate state laws on guns.

Individuals who violate the law face a class 2 misdemeanor on the first offense and a felony charge on subsequent offenses.

Dealers found to have violated the law shall have their licenses revoked.

State Rep. Andy Boesenecke, a Democrat who co-sponsored the bill, said in a statement after the signing that the legislation "will help save lives and prevent future tragedies in Colorado."

Everytown for Gun Safety, which advocates for gun restrictions, was among the organizations praising the bill.

"Colorado's new law is the definition of common sense: If you want to buy a military-style rifle that can kill dozens without needing to reload, you need to get a permit that requires passing a background check and taking a safety course," John Feinblatt, president of the group, said in a statement.

Other groups said the bill infringes on constitutional rights.

Ian Escalante, executive director of Rocky Mountain Gun Owners, said in a video that the bill is "the worst, most sweeping gun restriction in U.S. history."

Escalante said the group is reviewing its legal options.

"We're not going to stand for it. We're not going to allow Jared Polis ... and the legislature to force us to buy back our right to purchase the most commonly-used rifle in America," he said.

The U.S. Supreme Court in 2024 struck down a federal ban on bump stocks.