Duncan v. Bonta: Large-Capacity Magazine Challenge

Duncan v. Bonta (originally Duncan v. Becerra) is the most consequential challenge to California's ban on possession of large-capacity magazines (LCMs), defined as magazines capable of holding more than 10 rounds. The case has produced a complex procedural history spanning nearly a decade and has now reached the Supreme Court's doorstep.^[1]

Background: Proposition 63 and SB 1446

California first banned the manufacture and sale of LCMs in 2000 but allowed continued possession of previously owned magazines. In 2016, both SB 1446 (signed by Governor Brown) and Proposition 63 (approved by voters) eliminated the possession exemption, requiring owners to dispose of, modify, or surrender their LCMs.^[2]

Judge Benitez's 2017 Injunction

In June 2017, U.S. District Judge Roger Benitez of the Southern District of California issued a preliminary injunction blocking enforcement of the possession ban, finding that plaintiffs were likely to succeed on the merits. He later issued a permanent injunction in March 2019, striking down the ban as unconstitutional.

Freedom Week (March 29 - April 5, 2019)

Between Judge Benitez's ruling on March 29, 2019 and the Ninth Circuit's stay on April 5, 2019, California residents could legally purchase standard-capacity magazines. Hundreds of thousands of magazines were sold during this period, now commonly referred to as "Freedom Week." Magazines acquired during Freedom Week remain legal to possess under the court's order.

First Ninth Circuit En Banc Decision (2021) and SCOTUS GVR

A three-judge panel of the Ninth Circuit affirmed Judge Benitez's ruling 2-1 in August 2020. California sought en banc rehearing, and in November 2021, an 11-judge en banc panel reversed, upholding the magazine ban under the two-step means-end scrutiny framework. Following the Bruen decision in June 2022, the Supreme Court granted certiorari, vacated the en banc decision, and remanded for reconsideration under the text, history, and tradition framework.^[3]

Judge Benitez's Post-Bruen Ruling (September 2023)

The case returned to Judge Benitez on remand. On September 22, 2023, he again struck down the LCM ban, declaring Section 32310 "unconstitutional in its entirety" and applying the Bruen framework. Judge Benitez found no historical tradition supporting a restriction on the number of rounds a magazine may hold. The state appealed, and in October 2023, the Ninth Circuit stayed Benitez's ruling pending appeal, keeping the LCM ban enforceable except as to Freedom Week magazines.^[4]

Ninth Circuit En Banc Decision (March 20, 2025)

On March 20, 2025, the Ninth Circuit issued its second en banc opinion in Duncan v. Bonta, this time applying the Bruen framework. In a 7-4 decision, the court upheld California's large-capacity magazine ban.^[5]

Judge Graber authored the majority opinion, holding that LCMs are not "arms" protected by the Second Amendment. The majority reasoned that LCMs are "optional accessories to firearms, and firearms operate as intended without a large-capacity magazine." Because the plain text of the Second Amendment does not cover LCMs, the court found that Section 32310 does not implicate the right to keep and bear arms. The majority also concluded that even if LCMs were arms, the ban is consistent with the nation's historical tradition of firearms regulation, citing Founding-era gunpowder storage laws as analogous restrictions on the quantity of dangerous materials that could be kept.

Judge Bumatay dissented, joined by Judges Ikuta, R. Nelson, and VanDyke. The dissent argued that the majority's distinction between firearms and their magazines is "untenable" and that the Bruen framework makes the magazine ban presumptively unconstitutional because the plain text of the Second Amendment protects the possession of arms and their attendant components.

Petition for Certiorari (August 2025)

On August 15, 2025, plaintiffs filed a petition for a writ of certiorari to the United States Supreme Court (Docket No. 25-198).^[6] The petition presents two questions: (1) whether a ban on the possession of common ammunition feeding devices violates the Second Amendment; and (2) whether a law requiring citizens to surrender lawfully acquired property without compensation violates the Takings Clause of the Fifth Amendment.

Multiple amicus briefs have been filed in support of the petition, including briefs from firearms rights organizations and several state attorneys general.

Current Status (May 2026)

As of May 2026, the Supreme Court has distributed the case for conference at least 14 times -- on November 21, December 5, December 12, January 9, January 16, January 23, February 20, February 27, March 6, March 20, March 27, April 2, April 17, and May 1, 2026 -- without granting or denying review. The persistent relisting, now spanning more than five months since the petition was filed, signals active internal deliberation. SCOTUSblog has identified Duncan as among the strongest candidates for a cert grant in the current term. On March 11, 2026, the petitioners filed a supplemental brief addressing a related case.

The LCM ban remains enforceable statewide. Magazines acquired during Freedom Week (March 29 - April 5, 2019) remain legal to possess under the original injunction.