DOJ Sues Colorado Over State Ban on ‘Large-Capacity’ Magazines

The Trump administration sued Colorado over the state’s ban on “large-capacity” magazines, saying it violates the Second Amendment.

The Justice Department filed its complaint Wednesday in the US District Court for the District of Colorado a day after it sued Denver over its prohibition on assault-style firearms such as the AR-15.

The Colorado law makes it a misdemeanor to possess or sell large-capacity magazines, such as those holding more than 15 rounds of ammunition.

The DOJ’s complaint rejects the phrase “large-capacity” as “tendentious” and “politically charged,” saying the magazines are standard for popular firearms including the AR-15.

Citing the US Supreme Court’s 2022 decision in N.Y. State Rifle & Pistol Ass’n v. Bruen, the complaint argues the law is unconstitutional because the magazines are in common use for lawful purposes.

“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,” Wednesday’s complaint says. “The State’s magazine ban is a ban on an arm in common use for lawful by law-abiding citizens.”

In a statement, Colorado Attorney General Phil Weiser said, “Using federal civil rights law to put Coloradans at greater risk of gun violence is a dangerous overreach by the Justice Department.”

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

The complaints against Colorado and Denver were both signed by Barry Arrington, a notable gun-rights attorney who recently joined the Justice Department and is listed as the Acting Chief of its Second Amendment Section.

Harmeet Dhillon, the DOJ’s Assistant Attorney General for Civil Rights, has put significant focus on Second Amendment issues. During her tenure at the Civil Rights Division, the DOJ has also brought challenges to firearm restrictions in jurisdictions including Los Angeles and Washington.

The case is United States v. Colorado, D. Colo., No. :26-cv-01950, complaint 5/6/26.