DOJ Files Second Colorado Lawsuit in 24 Hours, Targets State’s 15-Round Magazine Ban as Civil Rights Violation

Estimated reading time: 7 minutes

DENVER, CO — The United States Department of Justice has filed its second federal lawsuit in 24 hours challenging Colorado firearms restrictions, this time targeting the state’s ban on so-called “large capacity” magazines holding more than 15 rounds.

The complaint was filed on May 6, 2026 in the U.S. District Court for the District of Colorado as Case No. 1:26-cv-01950, United States of America v. State of Colorado and Colorado Department of Public Safety. The lawsuit comes one day after the DOJ filed United States v. City and County of Denver, previously covered by USA Carry, which targets Denver’s local AR-15 ban. Both cases are being prosecuted by the DOJ Civil Rights Division’s Second Amendment Section under Acting Chief Barry K. Arrington and Assistant Attorney General Harmeet K. Dhillon.

The Magazine Ban Being Challenged

The lawsuit targets Colorado Revised Statutes Section 18-12-302, which makes it a Class 1 misdemeanor to sell, transfer, or possess a “large capacity magazine” within Colorado. The statute defines that term as any fixed or detachable magazine, box, drum, feed strip, or similar device capable of accepting more than 15 rounds of ammunition, along with restrictions on shotgun magazines.

The DOJ’s complaint refuses to use the state’s terminology. The filing explicitly states that “The Magazine Ban uses politically charged rhetoric to describe the arms it bans,” and notes that magazines holding more than 15 rounds “are, in fact, standard capacity magazines for many popular firearms, including the AR-15 rifle, the most popular rifle in America.”

The complaint refers to the items as “Banned Magazines” rather than “large capacity magazines” throughout, signaling the same direct rhetorical pushback the Denver complaint applied to the term “assault weapon.”

Magazines Are Arms Under the Second Amendment

The DOJ’s legal argument is structured around two pillars from the Heller and Bruen decisions. First, that magazines are protected arms under the Second Amendment. Second, that they are in common use today by law-abiding Americans for lawful purposes.

On the first point, the complaint cites the predicate-act canon of statutory interpretation, the doctrine that when a constitutional right authorizes a certain act, it implicitly authorizes whatever is necessary to perform that act. The DOJ also cites Justice Clarence Thomas’s concurrence in Luis v. United States and federal appellate decisions including Association of New Jersey Rifle and Pistol Clubs v. Attorney General New Jersey, which directly held that magazines are arms within the meaning of the Second Amendment because they are necessary for semiautomatic firearms to function as designed.

The complaint puts it plainly. Semiautomatic pistols and rifles cannot function as designed without a magazine.

Colorado’s Own Stipulations Used Against the State

The complaint deploys a powerful tactical move. It quotes back to Colorado the stipulations the state itself entered into in two prior cases, Colorado Outfitters Association v. Hickenlooper (2013) and Rocky Mountain Gun Owners v. Hickenlooper (2013).

In those cases, when defending the magazine ban, the State of Colorado stipulated to facts that now form the basis of the federal challenge. Among those stipulations:

• More than 300,000,000 firearms are lawfully owned in the United States
• A significant percentage of privately owned firearms are semiautomatic, most of which use detachable box magazines
• The number of lawfully owned semiautomatic firearms in the United States that use magazines like those banned by Colorado is in the tens of millions
• Several million AR-15 platform rifles have been lawfully purchased in the United States and are used for lawful purposes
• In states without magazine restrictions, AR-15 platform rifles are usually sold with 30-round magazines, and the majority of AR-15 owners use 20 or 30 round magazines
• Many full-sized 9mm semiautomatic pistols, including the Glock 17, are sold at retail with magazines holding more than 15 rounds
• The number of magazines like those banned by Colorado in the United States is in the tens of millions
• In Colorado alone, the number of such magazines is in the millions
• Prior to the effective date of the magazine ban, magazines like those banned were not unusual in Colorado

The DOJ’s argument writes itself. Colorado has already admitted under oath that the magazines it banned are in common use by law-abiding Americans for lawful purposes, including self-defense. Under Bruen, that admission is fatal to the state’s ability to defend the ban, because there is no historical tradition of banning arms in common use.

The 448 Million Number

The complaint also cites the National Shooting Sports Foundation’s Detachable Magazine Report covering 1990 through 2021, which estimates at least 448 million magazines with capacity exceeding 15 rounds in the United States.

That number puts the common use question to rest. With 448 million such magazines in circulation, the items the State of Colorado has chosen to criminalize are owned by roughly two for every adult American.

The Civil Rights Statute Strategy

As with the Denver lawsuit, the DOJ is bringing this case under 34 U.S.C. Section 12601, the federal statute that allows the Attorney General to sue local governments for patterns or practices of unconstitutional conduct by law enforcement officers.

The complaint argues that Colorado State Patrol officers and Colorado Bureau of Investigation agents are under a statutory duty to enforce the magazine ban, that they have routinely done so since 2013, and that they will continue to do so unless enjoined. Those enforcement actions, the DOJ contends, deprive Colorado residents of their Second Amendment rights and constitute a pattern or practice of unconstitutional conduct under federal civil rights law.

The relief sought includes a declaratory judgment that Colorado and the Department of Public Safety are governmental authorities under the statute, that their officers’ enforcement of the magazine ban constitutes a pattern or practice depriving people of constitutional rights, and a permanent injunction barring continued enforcement of the ban.

This @CivilRights Division’s Second Amendment Section is firmly protecting every law-abiding citizen’s right to carry.

These rights do not protect themselves, & @TheJusticeDept & this administration will ensure that the Second Amendment is NOT a second-class right! pic.twitter.com/450MSBlc19

— AAGHarmeetDhillon (@AAGDhillon) May 6, 2026

Dhillon: First Time DOJ Has Defended Citizens’ Second Amendment Rights

Assistant Attorney General Harmeet Dhillon, who oversees the Second Amendment Section as part of the Civil Rights Division, addressed the broader strategy in a recent video posted to X.

“This is the first time, however, in American history, that the United States Department of Justice is on the side of the citizens in enforcing the Second Amendment,” Dhillon said. “I’m so excited and proud to be at the helm of that, with the full support of acting attorney general, Todd Blanche, who himself is an enthusiastic supporter of Second Amendment rights, goes to gun events with me, and others here at the DOJ.”

Dhillon noted that the DOJ has now sued Denver four times for what she described as illegal bans on lawfully permitted firearms, and that the Department is also tracking the Wolford v. Hawaii case currently before the Supreme Court, which challenges Hawaii’s restrictive concealed carry framework.

“These rights do not protect themselves, and that’s true of all of our civil rights,” Dhillon said. “We will eventually get to whatever jurisdiction you want to complain about in my DMs and my mentions on X. We will get there.”

That public commitment, paired with two lawsuits in two days targeting one state, signals that this is not a one-off action but the beginning of a sustained federal enforcement campaign against state and local firearms restrictions deemed inconsistent with Heller, McDonald, and Bruen.

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Why This Matters

The Second Amendment is a fundamental civil right, and federal civil rights enforcement is precisely the legal architecture designed to defend constitutional rights against state and local governments that violate them. The DOJ’s use of 34 U.S.C. Section 12601, a statute historically associated with police accountability, to enforce Second Amendment rights is a significant doctrinal step.

For armed citizens nationwide, the Colorado magazine ban lawsuit has implications that extend well beyond Colorado. Twelve states currently have some form of magazine capacity restriction, including California, New York, New Jersey, Connecticut, Massachusetts, Maryland, Hawaii, Illinois, Vermont, Washington, Oregon, and the District of Columbia. If the DOJ prevails in Colorado, the legal architecture established in this case provides a template for federal action against any of those states.

The use of Colorado’s own stipulations is also a significant teaching moment for state-level gun control advocates. Stipulating to factual realities in earlier cases, including the common use of banned items, can become evidence the federal government uses to invalidate the very laws those stipulations were intended to defend.

What Comes Next

The State of Colorado and the Colorado Department of Public Safety will have an opportunity to respond to the complaint. The case will proceed through motions practice and, eventually, to merits briefing or summary judgment.

Under Bruen, Colorado will bear the burden of demonstrating a historical analogue from the founding era for banning magazines holding more than 15 rounds. Given that the relevant historical period featured no comparable regulation and that magazines as a technology did not exist in the same form, that burden will be difficult to carry.

USA Carry will continue tracking both Colorado lawsuits and any additional DOJ filings as they develop.

The full text of the complaint is available on the Department of Justice website.