In a blow to gun control activists, the 9th U.S. Circuit Court of Appeals ruled on Friday that California's ban on large-capacity ammunition magazines is unconstitutional, violating the Second Amendment.

In a 2-1 decision, the panel of judges found that such firearm magazines are protected arms under the Second Amendment and are not "unusual arms" that would fall outside its scope.

Large-capacity magazines, also called high-capacity, are defined in the law as magazines that hold more than 10 rounds of ammunition. In recent years, they have been used in mass shootings ending in widespread carnage. The shooters behind attacks in Dayton, Ohio, and El Paso, Texas, in 2019 and the 2017 Las Vegas massacre all used such magazines to kill and injure dozens if not hundreds of people within minutes.

"California's near-categorical ban of LCMs [large-capacity magazines] infringes on the fundamental right to self-defense," Judge Kenneth K. Lee wrote in the majority opinion.

"It criminalizes the possession of half of all magazines in America today. It makes unlawful magazines that are commonly used in handguns by law abiding citizens for self-defense. And it substantially burdens the core right of self-defense guaranteed to the people under the Second Amendment."

"It cannot stand," he added.

However, Judge Barbara M. G. Lynn, who also served on the panel, disagreed.

In a dissenting opinion, Lynn noted that California is not the first city or state to ban the possession of large-capacity magazines and several other federal appeals courts have held that various restrictions are constitutional.

Still, the panel appeared sympathetic to the state's core mission in trying to preserve the law.

"We are keenly aware of the perils of gun violence. The heartbreak and devastation caused by criminals wielding guns cannot be overstated," Lee wrote.

To that end, the court made several recommendations on how the state could achieve that, including imposing waiting periods, requiring microstamping of guns and forbidding felons, the mentally ill or those convicted of domestic violence from owning firearms.

California Attorney General Xavier Becerra's office was disappointed with the ruling, though it remains unclear whether Becerra plans to ask the full court to consider the case or advance the issue to the U.S. Supreme Court.

"We are carefully reviewing the decision, with the goal of protecting public safety," an adviser in Becerra's office told NPR, adding that the stay on the injunction issued by the District Court remains in place.

"The Attorney General remains committed to using every tool possible to defend California's gun safety laws and keep our communities safe."

Although Friday's decision rolls back the ban on what are considered deadly ammunition magazines, it does not address the greater issue of the constitutional right to own assault-type weapons.

"We do not opine on bans on so-called 'assault weapons,' nor do we speculate about the legitimacy of bans on magazines holding far larger quantities of ammunition. Instead, we only address California's ban on LCMs as it appears before us," the court said.

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