An organization of gun owners mounted a new legal challenge to Colorado’s nearly decade-old ban on large-capacity magazines Thursday, citing a ruling by the U.S. Supreme Court last month that was seen as a major expansion of gun rights.

The National Foundation for Gun Rights, the legal arm of Rocky Mountain Gun Owners, sued Gov. Jared Polis in U.S. District Court in Denver, asking a federal judge to strike down as unconstitutional the state’s 2013 ban on magazines that hold more than 15 rounds of ammunition, enacted in the wake of the Aurora theater shooting.

The Colorado Supreme Court in 2020 unanimously upheld the ban, ruling in a lawsuit brought by Rocky Mountain Gun Owners in state court that the prohibition does not violate residents’ right to bear arms as guaranteed by the state Constitution.

But with the new challenge — this time in federal court — Rocky Mountain Gun Owners cite last month’s New York State Rifle & Pistol Association v. Bruen ruling, which found a gun-permitting law in New York violated the Second Amendment. The majority interpreted the Second Amendment as protecting people’s rights to carry a gun for self-defense outside the home.

The language in Justice Clarence Thomas’s majority opinion heightened concerns that state gun-control laws across the country, from setting age limits on firearm purchases to banning high-capacity magazines, may now be in jeopardy.

“In last month’s landmark Bruen decision, the U.S. Supreme Court rejected ‘intermediate scrutiny’ — the cost/benefit analysis framework that allowed lower courts to rule against the Second Amendment — and established that the standard for applying the Second Amendment is the text, history and tradition of the right to keep and bear arms; thereby, invalidating the lower court rulings’ justification for gun control,” Rocky Mountain Gun Owners said in its announcement of the lawsuit.

A spokesman for Polis said the governor’s office does not comment on pending litigation.

Rocky Mountain Gun Owners also filed a lawsuit earlier this month against the town of Superior over its new ban on large-capacity magazines and semi-automatic rifles. Last week, a federal judge granted a temporary restraining order preventing Superior from enforcing the ordinance, which the town adopted in concert with multiple Boulder County municipalities.

“The early wins in Superior are a telltale sign of what is to come not only in Colorado but around the entire country,” said Taylor Rhodes, executive director of Rocky Mountain Gun Owners, in a statement Thursday.

The lawsuit filed by Rocky Mountain Gun Owners against the state argues that Colorado’s prohibition on what the organization calls “standard-capacity magazines” is contrary to the Second Amendment and the rights of law-abiding Coloradans “who wish to possess these commonly owned firearm accessories,” according to a news release.

The state lawsuit names as plaintiffs Benjamin Gates and Travis Swartz, describing the pair as Colorado residents and “law-abiding citizens of the United States.” The pair currently own magazines that are capable of holding more than 15 rounds of ammunition.

The complaint contends that Colorado’s magazine ban “uses politically charged rhetoric to describe the arms it bans” and that the characterization of “large capacity” magazines is a misnomer.

“Magazines capable of holding more than 15 rounds are standard-capacity magazines,” according to the lawsuit.

The Glock 17, a 9 mm semi-automatic pistol, one of the most popular handguns sold in the United States and often used by law enforcement, is sold at retail with magazine capacities greater than 15, according to the complaint. “Although the total number of magazines of any size in Colorado is not known, the number of magazines with a capacity greater than 15 rounds is in the millions.”

In 2020, Colorado Supreme Court justices ruled that the ban is a “reasonable exercise of police power that has neither the purpose nor effect of nullifying the right to bear arms in self-defense” set out in the Colorado Constitution. The court did not consider whether the ban violates the Second Amendment of the U.S. Constitution.