Denver Assault Weapons BanWhat the 2026 DOJ lawsuit means

The Denver assault weapons ban is now at the center of a federal court fight that has Colorado gun owners paying close attention. On May 5, 2026, the U.S. Department of Justice filed a federal lawsuit against the City of Denver over its decades-old ordinance banning so-called assault weapons, including AR-15-style rifles. A day later, the DOJ followed up by suing the State of Colorado over its large-capacity magazine limit.

Both cases were filed by the DOJ’s newly formed Second Amendment Section, and both are now headed into federal court. If you own rifles, shoot regularly, or are just trying to keep your collection legal, this is the kind of news that actually matters to your range bag. Here at Franktown Firearms in Douglas County, plenty of folks have asked what this means for them. The short version: it depends a lot on which side of the county line you live on. Here’s the full breakdown.

The Denver assault weapons ban makes it a crime to carry, store, sell, manufacture, or otherwise possess firearms the city classifies as assault weapons, and the lawsuit asks a federal court to strike it down. That category includes AR-15-platform rifles, certain semiautomatic shotguns, and semiautomatic pistols above a set capacity. The DOJ’s complaint argues the ban sweeps in firearms that are in common use across the country and are therefore protected under the Second Amendment.

The federal government did not jump straight to court. Late in April, the DOJ sent Denver a demand letter offering to hold off if the city agreed to stop enforcing the ban, acknowledge it as unconstitutional, and accept a court order permanently blocking enforcement. Denver declined. City Attorney Miko Brown called the demand an overreach of federal power, and Mayor Mike Johnston publicly defended the ordinance, crediting it with helping keep certain weapons off city streets for decades.

Less than 24 hours after that public refusal, the DOJ filed suit. The case is being led by the Civil Rights Division’s Second Amendment Section, with attorney Barry Arrington, a former Colorado state representative, handling the litigation.

The Denver assault weapons ban is not new. The city has restricted these firearms since 1989, making it one of the oldest local bans of its kind in the country. The case against the Denver assault weapons ban leans on two major Supreme Court cases that every serious gun owner should know

The first is District of Columbia v. Heller from 2008, which held that the Second Amendment protects an individual’s right to keep firearms in common use for lawful purposes. The second is New York State Rifle and Pistol Association v. Bruen from 2022, which set the current test courts use to evaluate gun laws. Under Bruen, once a firearm is shown to be a protected “arm,” the government has to prove the restriction fits within the nation’s historical tradition of firearm regulation. The DOJ contends that because tens of millions of AR-15-style rifles are owned nationwide, they are clearly in common use, and that no historical tradition supports banning them.

Denver and gun-control legal groups see it differently. They argue the ordinance has survived legal scrutiny before, that similar bans have been upheld in other jurisdictions, and that the city has a strong public-safety interest in keeping the law on the books. This is a genuine legal dispute, not a settled question, and it will likely take a long time to work through the courts.

The Denver assault weapons ban case is only half the story. One day after suing the city, the DOJ filed a separate lawsuit against the State of Colorado over its limit on large-capacity magazines. Colorado law restricts magazines that hold more than 15 rounds, and the federal complaint argues that magazines are part of the “arms” the Second Amendment protects, making the limit unconstitutional.

This second suit is the one that reaches well beyond Denver’s city limits. Colorado Attorney General Phil Weiser has said the state will defend the magazine law in court, describing capacity limits as responsible policy aimed at reducing harm in mass shootings. The federal government argues the opposite. Whatever your view, the practical reality for now is simple: the state magazine limit remains in effect while the case is pending.

A lawsuit being filed does not change the law overnight. Nothing about these filings gives anyone a green light to ignore current Colorado statutes, and we’d urge everyone to keep their gear compliant until courts actually rule. None of this is legal advice, and if you have questions about your specific situation, talk to a Colorado attorney who handles firearms law.

Here’s the part that matters most locally, and it comes in two pieces. First, the Denver assault weapons ban is a City and County of Denver law. It does not apply in Douglas County and never has, so if you live in Franktown, Castle Rock, Parker, or Elizabeth, that specific city ban is not what governs your rifle.

But don’t mistake that for “nothing changes out here.” The bigger story for Douglas County is statewide, and it lands August 1, 2026. That’s when SB 25-003 takes full effect. After that date, buying a covered semiautomatic rifle, shotgun, or gas-operated pistol anywhere in Colorado requires a state-approved safety course and a Firearms Safety Course Eligibility Card from your county sheriff first.

The DOJ lawsuits are worth watching, but the change that will actually affect your next purchase is the August deadline, not a courtroom in Denver. We walk through the whole eligibility card and training process in our SB 25-003 guide, and we’d much rather you get ahead of it now than scramble in July.

The Denver assault weapons ban lawsuit will move slowly, but headlines move fast. The best thing you can do is tune out the noise and focus on what you control. Keep your firearms and magazines compliant with current Colorado law, hold onto receipts and documentation for your gear, and stay current on training so your skills stay sharp regardless of how the legal landscape shifts.

This is also a good moment to think about legal protection for yourself. If you carry, a self-defense legal coverage plan can give you peace of mind that the court system won’t catch you flat-footed. And if you’ve been meaning to get more comfortable with your rifle or pistol, structured range time and instruction beat scrolling court filings every time.

Our indoor range here in Franktown is open year-round, our instructors can train you on pistol and rifle fundamentals, advanced shooting and more. Our CCW certification and renewal classes keep your permit current. The law will do what the law does. Your job is to stay trained, stay legal, and stay calm while the lawyers argue.