A lawsuit filed in federal court by three Denver residents and two gun rights groups aims to strike down the city’s “assault weapon” restrictions, along with bans on ammunition magazines holding 15 rounds or more.

The complaint, filed on June 30 by Ray Elliott, Trevor Alley and Michael Vitco, along with the Firearms Policy Coalition and the Colorado State Shooting Association, an arm of the National Rifle Association, alleges Denver’s semiautomatic firearm ban is unconstitutional, as is its ban on 15-round or larger magazines.

Naming the city government, Colorado Gov. Jared Polis, Attorney General Phil Weiser, Colorado Bureau of Investigation Director Armando Saldate III, Colorado State Patrol Chief Col. Matthew Packard and Denver District Attorney John Walsh, the complaint seeks a permanent injunction under federal rules requiring the city to end its “unconstitutional” practices, implement reforms and prevent future constitutional violations.

Passed in 1989, Denver’s longstanding ban on assault-style weapons restricts the possession and sale of guns with magazines carrying more than 15 rounds.

According to court documents, the plaintiffs are seeking to legalize the ownership of semiautomatic weapons in Denver and Colorado for “law-abiding” and “responsible” adults for “lawful” purposes, including home defense, target shooting and practice and self-defense. 

The plaintiffs are asking for an award of attorney fees and costs.

“Every day these bans remain on the books, law-abiding Coloradans are denied their fundamental right to keep and bear arms that are in common use across the country,” Kolby Zipperer, vice president of CSSA, said in a press statement. “The courts — not politicians in Denver — will decide whether the Second Amendment means what it says.”

This lawsuit comes on the heels of previous federal action by the Trump administration on the same matter, and Denver Mayor Mike Johnston has vowed to defend the city’s position.

“We will not be intimidated out of keeping Denver safe, least of all by this president or the NRA,” Johnston said in a press statement Tuesday. “This law saves lives, and we will fight to keep it in place and keep assault weapons off our streets.”

In May, less than 24 hours after a defiant Johnston publicly rebuffed the U.S. Department of Justice’s demand to repeal the city’s ban on semiautomatic weapons, the Trump administration followed through with its threat to take the matter to court.

The demand, in the form of a letter from the DOJ, stated that it would sue if Denver did not comply with specific “pre-suit” negotiations to resolve the matter.

“Our answer is hell no,” Johnston told a crowd gathered at the time at City Hall. “No, we will not roll back a common-sense policy that has kept weapons of war off of these city streets for 37 years. No, we will not put first responders at greater risk every time they respond to a dangerous incident. No, we will not go back to a time when folks are worried about walking into movie theaters, grocery stores or public elementary schools.”

City officials assert that Denver retains “clear legal authority to regulate firearms within its borders to protect public safety, and the ordinance is consistent with both Colorado law and the U.S. Constitution.”

“This ordinance is not unconstitutional, no question about it,” Denver City Attorney Miko Brown said in response to the Trump administration’s challenge, noting that the almost four-decade-old law has been tested and upheld in six different courts of appeals.

“These are not assault weapons that are in common use and regularly used for self-defense,” Brown added. “So we feel really confident that if we are challenged, we will prevail.”

“In an era when gun violence is a top public safety concern, these laws give law enforcement and prosecutors the tools we need to protect the community, in full compliance with the Second Amendment,” said Walsh. “As Supreme Court Justice Antonin Scalia himself explained, the right to bear arms under the Second Amendment is not unlimited — these commonsense laws protect community safety and Second Amendment rights at the same time. We look forward to establishing that in court, yet again.”

However, gun-rights groups argue that the banned firearms and magazines are “commonly possessed” and cannot be banned as “dangerous and unusual.”

“We filed this lawsuit to end Denver and Colorado’s war on gun owners and force these tyrants to respect the Second Amendment, whether they like it or not,” said Brandon Combs, president of FPC. “This case is another critical step in our nationwide campaign to eliminate tyrannical bans on constitutionally protected firearms and magazines.”

Johnston has long made public safety the centerpiece of his administration, with homicides falling last year to the second-lowest rate since 1990.

Although Denver just recorded one of the city’s lowest homicide totals, 37 in 2025, Johnston has said that progress is off track.

As of the city’s March 31 data, Johnston said that firearm-related homicides were flat, “not up, not down.”

The data did not include the latest string of shootings during the first weeks of April.