The U.S. Court of Appeals for the Ninth Circuit ended California's challenge to a portion of the federal frame-and-receiver rule on August 21, holding that the state and Giffords Law Center lacked standing. The panel vacated a district court order that had declared the rule's Example 4 unlawful and remanded with instructions to dismiss the case without prejudice. The decision addresses who may sue, not whether the Bureau of Alcohol, Tobacco, Firearms and Explosives drew the correct regulatory line.

The disputed AR-15 receiver example

ATF's 2022 final rule expanded the regulatory definitions of frame and receiver to include some partially complete, disassembled, and nonfunctional items that may readily be completed or converted. Example 4 says an AR-15 variant receiver billet or blank is not a receiver when critical interior areas have not been indexed, machined, or formed and the item is not sold, distributed, or possessed with instructions, jigs, templates, equipment, or tools that make ready completion possible. California and Giffords argued that this example excludes too many early-stage receivers.

The plaintiffs did not seek to vacate the entire final rule. They challenged Example 4 and later ATF determinations that applied it, alleging violations of the Administrative Procedure Act. The district court found standing, ruled for ATF on the claim that Example 4 was contrary to law, but ruled for the plaintiffs on their arbitrary-and-capricious claim. It then declared Example 4 unlawful, vacated it, and sent the matter back to ATF. The federal government appealed that order.