Colorado bans guns with detachable magazines to prevent mass shootings

On Thursday, Polis signed Senate Bill 3, which bans the manufacture and sharply limits the sale of certain semiautomatic firearms in Colorado. The law is meant to reduce mass shooting casualties. "Gun-control groups hail the measure as a bold step toward reducing the death toll in mass shootings because attackers won’t be able to easily reload when they run out of bullets," the Wall Street Journal reported.

“I really think this will make Colorado safer,” Polis said before signing the bill at the state Capitol.

Starting in August 2026, it will be illegal to manufacture specific semiautomatic guns in the state if they can accept detachable magazines. The sale of these firearms will also be heavily restricted, according to the Colorado Sun.

The list of banned weapons includes AR-15 and AK-47 style rifles, tactical shotguns, and a small number of handguns. These weapons would only be available for purchase by eligible individuals if they are sold with magazines that are permanently fixed and cannot hold more than 15 rounds. According to experts, very few guns like that are currently produced.

The new law also immediately bans devices such as bump stocks that can make semiautomatic weapons fire at speeds close to fully automatic firearms.

Semiautomatic weapons fire once per trigger pull. Automatic firearms continue firing as long as the trigger is held down.

There are some exceptions in the bill. It allows these banned firearms to still be made in Colorado for use by the military, law enforcement, correctional officers, or armored vehicle companies. Gunsmiths can also repair the weapons. However, most of these types of guns aren’t made in Colorado to begin with, so the manufacturing part of the law is expected to have limited effect.

Even though rapid-fire trigger devices are now completely banned, there’s still a path for some people to legally buy firearms that fall under Senate Bill 3’s restrictions. They can do so by getting a “firearms safety course eligibility card.”

To receive this card, a person must go through a background check by their county sheriff. Sheriffs will have wide discretion and can deny anyone they see as a risk. If someone is denied, they can try to challenge it in court.

If approved, applicants must complete up to 12 hours of training—depending on their background—and pass a written test. Once they’ve done that, they’re allowed to buy one of the restricted weapons. The eligibility card lasts for five years and must be renewed to buy more firearms under the law.

Some may think about buying a banned gun out of state, but that would still break federal law. Gun dealers must follow the rules of the buyer’s home state, meaning someone from Colorado can’t legally bypass the new restrictions by purchasing a weapon elsewhere.

Breaking the law comes with consequences: A first offense under Senate Bill 3 would be a Class 2 misdemeanor, which can result in up to 120 days in jail and a fine. A second offense would be a Class 6 felony, carrying a penalty of up to 18 months behind bars. Possessing a rapid-fire trigger device is now a Class 5 felony, with penalties of up to three years in prison. Further offenses increase the charge to a Class 4 felony.

Gun rights groups have promised to sue over Senate Bill 3, arguing that it’s unconstitutional. A court battle could delay or even stop the law from taking effect. But if it goes forward, it will mark a major shift in how Colorado handles firearms.