On May 6, 2026, the U.S. Department of Justice (DOJ) filed suit against the state of Colorado arguing that Colorado unconstitutionally bans constitutionally protected standard capacity firearm magazines. The DOJ claims the law unconstitutionally infringes on the Second Amendment rights of law-abiding citizens to keep and bear arms.  

Colorado law makes it a misdemeanor to possess or sell large-capacity magazines, such as those holding more than 15 rounds of ammunition. The law was passed after a 2012 mass shooting at a move theater in Aurora, Colorado that left 12 people dead and more than 70 wounded. Supporters of the legislation argued that the restrictions are necessary to curb mass shootings, and that they promote safety.  

In its lawsuit, the DOJ argues that the magazines targeted by Colorado legislation are not actually “large capacity” magazines. The DOJ argues they are standard magazines used in many popular weapons such as AR-15 rifles, and as such at the law violates citizens’ Second Amendment rights by prohibiting access to the detachable magazine that is commonly used. DOJ is requesting the court issue a declaratory judgment that the state of Colorado and the Colorado Department of Public Safety are violating federal law by enforcing the magazine ban. The DOJ is also seeking permanent injunctive relief to prohibit the defendants and their agents from enforcing the ban and to mandate the adoption of policies and procedures to remedy the alleged unconstitutional conduct. 

Using federal civil rights law to put Coloradans at greater risk of gun violence is a dangerous overreach by the Justice Department and this lawsuit turns the mission of the DOJ’s Civil Rights Division on its head. Large-capacity magazine laws are responsible policies that satisfy Second Amendment protections, decrease the deadly impacts of mass shootings, and save lives. The state has a duty to protect Colorado residents from gun violence, and I will vigorously defend our state large-capacity magazine limit law from this attack by the Trump Justice Department.Attorney General Phil Weiser