California Passes Conditional Ban on 3D Printers Without Firearm-Blocking Software

California lawmakers approved AB 2047, creating a pathway for the state to require 3D printers to inspect and block firearm-related design files.

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California AB 2047 could require 3D printers sold in the state to inspect digital files and block print jobs involving firearms or machine-gun conversion devices. Credit: AI-generated editorial image created for AmmoLand News.

California has passed AB 2047, the California Firearm Printing Prevention Act, and the bill is now on Governor Gavin Newsom’s desk.

The measure, authored by Assembly Member Rebecca Bauer-Kahan, would eventually require consumer 3D printers sold or transferred in the state to include “firearm blocking technology” intended to identify and stop print jobs for firearms and certain illegal parts, including machine-gun conversion devices. After weeks of amendments, the Legislature sent the enrolled bill to the governor in the closing hours of the 2026 session. Newsom has until the end of September to sign or veto it.

The version that reached his desk is far narrower than the bill that first cleared the Assembly in May. The Senate stripped several of the most aggressive enforcement tools after lawmakers and industry groups argued they were technologically infeasible or overbroad. Gone are the original criminal misdemeanor for disabling the software, the $25,000-per-violation civil penalties, the mandatory manufacturer self-attestation process, and a public roster of “compliant” models.

The final text keeps an exemption for printers used exclusively to make entertainment-industry props and lets the California Department of Justice create additional exceptions by regulation. It also shields people who share digital firearm files solely to test or develop blocking software.

What remains is a delayed, contingent mandate. Beginning no later than July 1, 2027, the DOJ must check quarterly whether ASTM International has published industry standards for firearm-blocking technology on 3D printers. If ASTM issues qualifying standards, the department then has 24 months to publish its own written guidance or regulations describing minimum performance requirements. One year after those state standards appear, it would become unlawful to sell, offer for sale, or transfer a 3D printer in California that lacks compliant blocking technology. If ASTM has not published standards by July 1, 2029, the department is relieved of further duties under the act, and the sales restriction may never take effect.

The bill does not operate in a vacuum. California already prohibits unlicensed people from using a 3D printer or CNC mill to manufacture a firearm under Penal Code § 29185. Separate statutes restrict machines whose “sole or primary function” is to make guns and create civil liability for distributing “digital firearm manufacturing code” to unlicensed persons. AB 1263 and related 2025–26 measures further expanded definitions of firearm manufacturing machines and accessories effective January 1, 2026. AB 2047 tries to move one step upstream by making the printer itself refuse certain files.

California is not the first state down this path. New York enacted a similar blocking-technology law earlier this year. Sacramento modeled AB 2047 on that approach, then made the California version more conditional after the Senate rewrite.

Critics say the concept still fails on both technology and law. 3D-printing companies, the ACLU of California, Hollywood prop shops, the Electronic Frontier Foundation, and gun-rights groups argue that detection algorithms are easy to evade with slightly modified files, offline machines, older printers already in circulation, or out-of-state purchases. They also raise First Amendment concerns about treating design files as something the state can force hardware makers to censor, and they warn that unreliable software would burden schools, small businesses, and hobbyists. Several analyses noted that the Senate rewrite left the actual sales ban hanging on a private standards body that may never act.

Supporters, including Everytown for Gun Safety and the bill’s author, frame AB 2047 as a response to recovered 3D-printed guns and unfinished frames. They describe it as a way to cut off a pipeline for untraceable weapons before a file becomes a firearm.

Even if Newsom signs the bill, nothing changes at the store counter tomorrow. The mandate is years away, if it arrives at all. The practical fight now is whether ASTM writes a standard the state can adopt—and whether software that must inspect every print job can ever work well enough to survive both evasion and a courtroom.

About John Crump

Mr. Crump is an NRA instructor and a constitutional activist. John has written about firearms, interviewed people from all walks of life, and on the Constitution. John lives in Northern Virginia with his wife and sons, follow him on X at @right2bear, or at www.crumpy.com.