Latest Trump administration lawsuit targets Colorado's large-capacity magazine ban

Shelly Bradbury, The Denver Post on May 6, 2026

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DENVER — The U.S. Department of Justice sued Colorado on Wednesday over the state’s ban on large-capacity magazines, following up on a similar lawsuit the Trump administration brought to challenge Denver’s assault weapon ban a day prior.

The new lawsuit alleges that Colorado’s ban on ammunition magazines capable of holding more than 15 rounds violates the Second Amendment’s right for citizens to keep and bear arms. It argues that such magazines are standard for many weapons.

“Law-abiding Americans own and use for lawful purposes literally hundreds of millions of magazines such as those banned by the State,” the complaint reads. “A detachable magazine is an integral part of most semi-automatic firearms, including the AR-15 rifle. As such, they are covered by the Second Amendment’s right to keep and bear arms.”

Attorney General Phil Weiser vowed to defend the ban in a statement Wednesday, reiterating a stance he and other state and local officials took when the DOJ first threatened the lawsuits against Denver and the state earlier this week.

“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,” Weiser said in the statement. “Large-capacity magazine laws are responsible policies that satisfy Second Amendment protections, decrease the deadly impacts of mass shootings, and save lives.”

The Colorado Supreme Court upheld the state’s ban on large-capacity magazines in 2020, finding that the prohibition did not violate residents’ right to bear arms as guaranteed by the state Constitution. The decision did not consider whether the ban violated the Second Amendment to the U.S. Constitution.

State lawmakers passed the ban in 2013 in the wake of the Aurora movie theater shooting the prior year, in which the gunman used a large-capacity magazine to fire more than 60 rounds in less than a minute, killing 12 and wounding dozens.

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