PC 31910:
Microstamping Requirement

California Penal Code Section 31910 ^[1] formerly included a requirement that new semiautomatic pistols submitted for listing on the Certified Handguns Roster be designed and equipped with a microscopic array of characters that identify the make, model, and serial number of the pistol, etched or otherwise imprinted in two or more places on the interior surface or internal working parts of the pistol, and that are transferred by imprinting on each cartridge case when the pistol is fired.

How Microstamping Works

Microstamping technology uses a laser to engrave a microscopic code onto the tip of a firearm's firing pin (and potentially other internal components). When the gun is fired, the firing pin strikes the primer of the cartridge, transferring the engraved code onto the cartridge case. Law enforcement can then recover spent casings at a crime scene and read the microstamp to identify the specific firearm that fired the round.

Implementation Timeline

The microstamping requirement was enacted in 2007 through AB 1471 but was contingent on a certification by the DOJ that the technology was available and not encumbered by patents. Attorney General Kamala Harris certified the technology as available on May 17, 2013, triggering the requirement for all new semiautomatic pistol models submitted to the roster after that date. In its March 27, 2023 filing in Boland, California stated that no new semiautomatic pistols had been added to the roster since the microstamping requirement took effect.

DOJ Microstamping Viability Report (July 2025)

On July 18, 2025, the California DOJ released its Microstamping Technological Viability Report ^[2], concluding that microstamping technology is "technologically viable." The investigation, led by the DOJ's Bureau of Forensic Services, found that microstamping components installed in semiautomatic pistols can regularly produce legible microstamps on spent cartridge cases, including after sustained or repeated firing, without compromising firearm safety or function ^[3].

This report is the first milestone in the framework established by SB 452, which separated the microstamping requirement from the Unsafe Handgun Act roster and created a standalone restriction. Under SB 452, the DOJ must follow a series of implementation steps:

• Performance standards: Due by September 1, 2025
• Licensure applications: DOJ must begin accepting applications from microstamping technology providers by January 1, 2026
• Commercial availability assessment: DOJ must evaluate whether microstamping technology is commercially available at reasonable prices by July 1, 2027
• Potential dealer restriction: If the DOJ concludes the technology is commercially available, a restriction would prohibit California-licensed firearms dealers from selling or transferring any semiautomatic pistol that is not equipped with microstamping on or after January 1, 2028

Practical Impact on the Roster

The microstamping requirement has had a profound effect on the Certified Handguns Roster. The DOJ roster lists pistol models added after May 2013, including the SCC CALI 4 added on October 9, 2026. Existing models are subject to annual roster fees under Section 32015, which permits exclusion from the roster if the manufacturer fails to pay the required fee. As of October 16, 2026, the DOJ roster displays 1,003 entries representing 1,002 distinct models, and entire generations of popular pistol platforms (such as newer Glock, Smith & Wesson M&P, and Sig Sauer P320 variants) are absent from the roster.

Boland v. Bonta

The microstamping requirement has been challenged in Boland v. Bonta. In March 2023, Judge Cormac Carney granted a preliminary injunction against the microstamping requirement, the chamber load indicator requirement, and the magazine disconnect mechanism requirement ^[4]. The state appealed and sought a partial stay of the injunction against the chamber load indicator and magazine disconnect requirements, but did not seek a stay of the injunction against microstamping. This injunction has allowed some new handgun models to be added to the roster, including the Biofire Smart Gun (available for retail sale in California by April 30, 2025) and select Sig P320 Legion and Shadow Systems DR920 variants.

On March 25, 2024, the Ninth Circuit vacated submission of Boland pending the en banc decision in Duncan v. Bonta. On March 27, 2025, it ordered supplemental briefs addressing the decided Duncan case and whether remand was appropriate. The Ninth Circuit stayed the preliminary injunction as to chamber load indicators and magazine disconnect mechanisms on March 31, 2023. SB 452 removed the roster microstamping requirement effective January 1, 2024. The roster framework also faces a new federal challenge, United States v. California (C.D. Cal., filed July 1, 2026), the Department of Justice suit attacking the Unsafe Handgun Act roster together with AB 1127. The district court denied a temporary restraining order in that case on July 9, 2026.

The Boland injunction concerned the former roster microstamping requirement. SB 452 removed that requirement from Section 31910 and created a separate dealer restriction in Section 27533. Section 27533 provides for a restriction beginning January 1, 2028 if the DOJ makes the availability determination required by Section 27532(e), subject to exceptions including pistols manufactured or delivered to a dealer before that date and private-party transfers conducted through a licensed dealer.

2024 Legislative Changes

The roster's "one-for-three" rule, which required removal of three semiautomatic pistols added before July 1, 2022 and lacking a required chamber load indicator or magazine disconnect mechanism for each newly added semiautomatic pistol, was preliminarily enjoined by Judge Dana Sabraw in Renna v. Bonta (S.D. Cal.) on March 31, 2023. The status of the one-for-three rule depends on the outcome of that litigation. SB 452 removed the former roster microstamping requirement from Section 31910.

See also: Boland v. Bonta: Handgun Roster and Microstamping Challenge