A law requiring fixed magazines that hold no more than 15 rounds for certain types of semiautomatic firearms is set to come into effect in Colorado on Aug. 1.
The law also requires classroom training, background checks, and approval from law enforcement for an individual to receive a permit to purchase one of the affected firearms.
The legislation, which was signed into law by Gov. Jared Polis on April 10, 2025, was challenged in court the following September.
Second Amendment advocates say the law is a de facto “assault weapons” ban.
Rather than banning specific guns, Colorado SB25-003 lists the characteristics of firearms that must have a fixed magazine that holds no more than 15 rounds.
The new law bans detachable ammunition magazines for certain firearms without banning large classes of firearms, Polis stated when he signed the bill into law. Polis said the law’s main objective is public safety.
“I am focused on improving public safety and making Colorado one of the top ten safest states in the country,” Polis wrote in a signing statement that day. “This bill ensures that our Second Amendment rights are protected and that Coloradans can continue to purchase the gun of their choice for sport, hunting, self-defense, or home defense.”
Under the new law, popular AR and AK-style rifles, as well as other centerfire semiautomatic rifles, pistols, and shotguns with detachable magazines, would generally be prohibited unless the buyer or owner had taken a training class and purchased a permit, which will remain on file with the state.
The law establishes a process for purchasing specified guns that involves training, a fee, criminal background checks, and approval by the sheriff of the county in which a person resides.
“I oppose banning types of firearms,” Polis’s signing statement reads. “Proper gun safety education and training, however, are key components of public safety and responsible gun ownership.”
On July 28, the Colorado State Shooting Association (CSSA) issued a press release decrying the law as a violation of the Second Amendment and vowing to continue fighting it.
“This is an attack at the very core of what it means to be an American,” Huey Laugesen, CSSA executive director, stated in the press release.
He wrote that the law’s requirements will turn the principle of constitutional rights belonging to the people “on its head.”
“Law-abiding citizens who want to purchase the most common firearms in America will first have to ask the state for permission, pay government-imposed costs, complete mandated training, pass an examination and have their personal information recorded in a state database,” Laugesen stated.
Colorado state Sen. Tom Sullivan, a Democrat, authored the law. Neither he nor Polis responded to requests for comment by publication time.
At the time the law was signed, Sullivan said he agreed with Polis.
Sullivan said the state banned ammunition magazines capable of holding more than 10 rounds of ammunition in 2013. However, that ban was not being adequately enforced. Sullivan said the new law preserves the right to own the so-called assault weapons, while enforcing the ammunition restrictions.
“You can still have all the features that the AR still has. Except that the magazine will be attached,” Sullivan told The Epoch Times at the time of the bill signing.
Battle Goes to Court
On Sept. 2, 2025, the Second Amendment proponents sued the state in the U.S. District Court for the District of Colorado.
In the lawsuit, Del Toro v. Polis, the plaintiffs claim the law adds burdensome fees and other requirements that violate the Second Amendment. The plaintiffs say the law transforms the Second Amendment from a Constitutional right to a pay-to-play arrangement.
“A government that makes you ask permission to buy a firearm isn’t protecting your rights—it’s trampling them,” CSSA President Ray Elliott said in a statement released the day the lawsuit was filed.
In the most recent press release, Laugesen said that the state has still not defined which firearms are covered or which vendors will be authorized to perform required background checks, making it virtually impossible to get the required permit.
“This permit-to-purchase scheme will be a de facto ban on semi-automatic rifles, shotguns, pistols, lowers, and parts kits that they’ve failed to define,” Laugesen wrote. “CSSA opposed this law from the beginning, and we will never accept this system as the new normal.”
