California to Mandate Gun-Blocking Function in 3D Printers

A Bill That Could Change 3D Printer

Manufacturing Norms The California State Assembly has passed bill “AB 2047,” mandating that all 3D printers sold within the state be equipped with “firearm-blocking technology,” and has sent it to the State Senate. Officially titled the “California Firearm Printing Prevention Act,” this bill is drawing attention for its stringency, which surpasses similar legislative efforts in states like New York, Washington, and Colorado. The bill was introduced in February 2026 by Assemblymember Rebecca Bauer-Kahan. After amendments on May 18, it was referred for a third reading the following day and subsequently passed by the full Assembly.

Core Provisions and Implementation Schedule

The core of AB 2047 is to require all 3D printers sold in California to incorporate firearm-blocking technology that screens design files before a print job begins. The implementation schedule is as follows: The California Department of Justice (DOJ) will investigate existing firearm design detection algorithms and publish performance standards by January 1, 2028. Printer manufacturers must submit sworn statements for each model by July 1, 2028, with false statements punishable as perjury. The DOJ will publish a list of compliant models by September 1, 2028, and starting March 1, 2029, non-compliant printers sold within the state may face civil penalties of up to $25,000 per violation.

Criminalization of Circumvention Sparks

Controversy What decisively sets AB 2047 apart from similar bills in other states is the presence of a “circumvention prohibition clause.” This clause makes it a misdemeanor for users to disable or bypass the firearm-blocking technology. The Electronic Frontier Foundation (EFF) has strongly opposed this provision. According to the EFF’s analysis, the bill would mandate “censorware” on all 3D printers, stripping users of the right to modify their own equipment. EFF’s Cliff Brown and Laurie Mill warn that this clause will create manufacturer ecosystem lock-in, bringing the same issues of consumable lock-in and planned obsolescence seen in 2D inkjet printers to the 3D printing world.

Impact on Open-Source Firmware The EFF is

particularly concerned that this circumvention prohibition clause would effectively criminalize the use of third-party open-source firmware. In the 3D printer enthusiast and maker community, open-source firmware like Marlin and Klipper is widely used. A major appeal of this firmware is that it allows users to finely customize their printer’s operation. However, under AB 2047’s circumvention prohibition, simply replacing the manufacturer’s firmware with one that does not include the official blocking technology could itself be considered an illegal act. Furthermore, selling a used printer excluded from the DOJ’s compliance list also carries the risk of being charged with a misdemeanor. This point is already causing significant waves in the maker community, posing a serious challenge from the perspectives of 3D printer DIY culture and the Right to Repair.

Technical Challenges and Privacy Concerns The

bill does not require a perfect detection rate and stipulates that performance standards must consider both false positives and false negatives. However, opponents point out several fundamental technical challenges. First, firearm components often share geometric shapes with common mechanical parts, making it difficult to accurately identify firearm components from design files. Moreover, even minor edits to a file can change its digital signature, potentially allowing detection to be circumvented. Additionally, the computational power required for such detection analysis might exceed the processing capability of consumer printers. In that case, the checking process would be offloaded to remote servers, raising new issues regarding user privacy and network connectivity.

Supporters’

Claims and Aiming to Close Enforcement Gaps On the other hand, supporters argue that this measure fills a major gap in law enforcement. Assemblymember Bauer-Kahan’s office cited a case in Santa Rosa where three 3D printers and 167 firearms were seized, 150 of which had their serial numbers obliterated. Data from the gun control group Everytown for Gun Safety was also referenced. From the supporters’ viewpoint, as 3D printer technology advances, introducing technical guardrails on the printers themselves is an indispensable regulatory tool against the illegal manufacture of firearms.

The Road Ahead for AB 2047 AB 2047 now moves

to the State Senate for consideration. If it passes the Senate and is signed by the Governor, California will become the state with the most stringent regulations on 3D printers. The fate of this bill will be a significant case not only for the 3D printer industry but also for the open-source community, digital rights organizations, and the broader manufacturing sector, as it questions the balance between user rights and public safety. How manufacturers respond to the 2028 compliance deadline and how the open-source firmware community reacts will be key points of interest moving forward.