PC 16890-16900:
Large-Capacity Magazine Definitions

California Penal Code Section 16740 defines the term "large-capacity magazine," which is the cornerstone of the state's restrictions on ammunition feeding devices.^[1]

### Definition (PC 16740)

Section 16740 defines a "large-capacity magazine" as any ammunition feeding device with the capacity to accept more than 10 rounds. This definition applies regardless of the type of firearm the magazine is designed for. A magazine that has been permanently altered to hold no more than 10 rounds is not a large-capacity magazine. The capacity exclusion applies to a feeding device that has been permanently altered so that it cannot accommodate more than 10 rounds.

### Exceptions (PC 16740)

Section 16740 provides specific exceptions to the large-capacity magazine definition.^[2] The term does not include: a feeding device that has been permanently altered so it cannot accommodate more than 10 rounds; a .22 caliber tube ammunition feeding device; or a tubular magazine contained in a lever-action firearm. These exceptions are narrowly drawn and do not extend to other tubular magazine configurations.

### Legislative History

California first banned the manufacture, importation, and sale of large-capacity magazines in 2000 through SB 23. That original ban included a grandfathering provision: persons who lawfully possessed large-capacity magazines before January 1, 2000 could retain them. Proposition 63 (2016) and SB 1446 (2016) eliminated the grandfathering provision, requiring all large-capacity magazines to be removed from the state, destroyed, or surrendered to law enforcement by July 1, 2017.^[3]

### Duncan v. Bonta Litigation

The constitutionality of the large-capacity magazine ban has been the subject of protracted litigation in Duncan v. Bonta (formerly Duncan v. Becerra). In March 2019, Judge Roger Benitez struck down the possession ban, creating a seven-day window ("Freedom Week") during which Californians could legally purchase standard-capacity magazines. The Ninth Circuit initially upheld the district court through a three-judge panel before an en banc panel reversed. Following the Supreme Court's decision in New York State Rifle & Pistol Association v. Bruen (2022), the case was remanded for reconsideration. On September 22, 2023, Judge Benitez again struck down Section 32310 under the Bruen framework. The Ninth Circuit granted a partial stay pending appeal on October 10, 2023.

On March 20, 2025, the Ninth Circuit issued a second en banc opinion, upholding the LCM ban in a 7-4 decision.^[4] The majority held that large-capacity magazines are "optional accessories to firearms" and are not "arms" protected by the Second Amendment. Plaintiffs filed a petition for certiorari to the Supreme Court on August 15, 2025 (Docket No. 25-198).^[5] The Court distributed the case for conference repeatedly through the June 29, 2026 conference without granting or denying review. On June 30, 2026, the Court granted certiorari in Grant v. Higgins and Viramontes v. Cook County, consolidated cases presenting the question whether the Second and Fourteenth Amendments guarantee the right to possess AR-15 platform and similar semiautomatic rifles. The Duncan petition remains pending.

The definition and exceptions in Section 16740 remain operative law. The Ninth Circuit's en banc decision upheld the regulatory framework that relies on these definitions, but the pending cert petition at the Supreme Court means the ultimate constitutionality of the large-capacity magazine prohibition remains an open question.

See also: PC 32310: Large-Capacity Magazine Ban

See also: Duncan v. Bonta: Large-Capacity Magazine Challenge

See also: "Freedom Week" Magazines: What March 29 - April 5, 2019 Changed