Attorney General Bonta Releases Report, Finds Firearm Microstamping Technology Viable

OAKLAND — California Attorney General Rob Bonta today released a report finding that firearm microstamping technology is technologically viable when imprinting a unique microscopic array of characters, referred to as a microstamp, on spent cartridge cases discharged by a firearm into which a microstamped firing pin has been installed. This report follows recent amendments to the Unsafe Handgun Act, including requiring that new semiautomatic pistols must have microstamping capabilities that allow law enforcement to trace a shell casing to the pistol that fired it. The California Department of Justice’s (DOJ) investigation found that microstamping components installed in semiautomatic pistols regularly produce microstamps on spent cartridge cases discharged by these firearms, including after sustained or repeat firing. The investigation was led by DOJ’s Bureau of Forensic Services, performed in consultation with relevant legal and subject matter experts, and included input from stakeholders, who were invited to provide written comments relevant to DOJ’s technological viability investigation.

“My office’s investigation into the technological viability of microstamping components has found that this technology is viable,” said Attorney General Bonta. “Microstamping technology could help law enforcement match cartridges found at crime scenes directly to the firearms they came from. Today, my office released a report outlining the findings of our investigation in an effort to provide appropriate transparency as to the basis of our determination.”

Microstamping technology causes a firearm to imprint a unique microscopic code onto ammunition cartridge cases when a firearm is fired that identifies the firearm’s make, model, and serial number, helping law enforcement match cartridges found at crime scenes directly to the firearms they came from.  

In 2023, California Governor Gavin Newsom signed Senate Bill 452, authored by Senator Catherine Blakespear (D-Encinitas), which amended California’s Unsafe Handgun Act and added separate Penal Code provisions that adopted new requirements concerning microstamping components in semiautomatic pistols sold or transferred in the state. California Penal Code section 27532 required DOJ to investigate the technological viability of microstamping components. Beginning January 1st, 2028, the Unsafe Handgun Act will mandate that all semiautomatic handguns sold by licensed dealers must be verified as microstamping enabled. 

In the report, DOJ outlines the findings of the investigation, including:

• Engraved firing pins consistently leave legible microstamps on spent cartridge cases.
• In many tested firearms and ammunition types, microstamping components can reliably imprint all data needed to identify the firearm. 
• Even incomplete microstamps can yield useful leads for solving and prosecuting gun crimes.
• Using partial microstamps is equivalent to using partial fingerprints, license plates, or firearm serial numbers as investigative leads. 

This fall, DOJ will work to provide written guidance on performance standards for entities engaged in the business of producing microstamping components. Starting early next year, DOJ will start accepting applications for licensure of entities to engage in the business of producing microstamping components that meet these performance standards. 

A full copy of the report can be found here.