California Penal Code Section 31910 [1] includes a requirement that new semiautomatic pistols submitted for listing on the Certified Handguns Roster must 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. Since 2013, no manufacturer has submitted a new semiautomatic pistol model with microstamping capability, effectively freezing the semiautomatic pistol portion of the roster.
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. Because no manufacturer has implemented the technology, no new semiautomatic pistol models have been added since May 2013. Existing models remain on the roster as long as manufacturers pay the annual renewal fee, but any lapse in renewal permanently removes the model. The roster has declined from over 1,200 models in 2013 to approximately 800 as of early 2026, 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 did not seek to overturn the injunction against microstamping. This injunction has allowed some new handgun models to be added to the roster, including the Biofire Smart Gun (certified February 2025) and select Sig P320 Legion and Shadow Systems DR920 variants.
As of early 2026, Boland has been vacated and pended to the en banc panel's resolution of Duncan v. Bonta. The preliminary injunction against microstamping, CLI, and MDM remains in effect while the case awaits its turn before the eleven-judge en banc panel.
The relationship between the Boland injunction and the DOJ's SB 452 viability report creates an unusual situation: the DOJ has found the technology viable and is proceeding with implementation steps, while the federal court injunction continues to prevent enforcement of the microstamping requirement. If the en banc panel upholds the roster framework and the injunction is dissolved, the SB 452 timeline could result in a January 1, 2028 enforcement date for mandatory microstamping.
2024 Legislative Changes
The roster's "one-for-three" rule, which required three existing models to be removed for each new model added, 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. However, without resolution of the microstamping requirement, the removal of the one-for-three rule alone does not enable new semiautomatic pistol additions.
See also: Boland v. Bonta: Handgun Roster and Microstamping Challenge