A US district judge struck down on Friday a California ban limiting gun magazines to ten rounds. In the decision, US District Judge Roger Benitez stated that the state’s prohibition of high-capacity magazines was a violation of the US Constitution’s Second Amendment and “clearly unconstitutional.”

In defense of the ban, California offered two main positions. First, the state argued that ammunition and magazines are not “arms” under the Second Amendment. But Benitez firmly rejected the argument by including “ancillary” components necessary to operate a firearm under Second Amendment protection. He cited federal precedent in several cases and concluded that, “while the Second Amendment does not explicitly mention ammunition or magazines supplying ammunition, without bullets, the right to bear arms would be meaningless.”

The state additionally argued that, even if some magazines are part of an “arm,” magazines holding more than ten rounds should fall outside that definition. The argument was based on the Second Amendment right to bear arms for self-defense. California asserted that people rarely fired ten or more rounds in the act of self-defense. As a consequence, magazines with a capacity of over ten rounds are not commonly used in self-defense and should not be classified as an “arm.”

Benitez also disagreed with this position. He stated, “There is no American tradition of limiting ammunition capacity and the 10-round limit has no historical pedigree and it is arbitrary and capricious.” Underlying the decision was the lack of current federal regulation and a lack of consensus amongst the states on magazine capacity limits.

California Attorney General Rob Bonta filed an appeal the same day as the decision. In a statement, he said, “We will move quickly to correct this incredibly dangerous mistake.”

California’s ban was instituted in 2016 after a majority of the state’s residents voted in favor of Proposition 63. In addition to the high-capacity magazine ban, the proposition mandated more extensive background checks, licensing of firearm dealers and other restrictions.

The decision is the latest blow to California’s attempt to regulate firearms. An earlier September decision enjoined a law that banned marketing of guns to minors.