California Passes Bill Requiring 3D Printers to Block Firearm Files

California lawmakers sent a conditional ban on 3D printers without firearm-blocking software to Governor Gavin Newsom's desk on September 2. The bill, AB 2047, would eventually require any consumer 3D printer sold or transferred in the state to include software capable of identifying and stopping print jobs for guns and certain illegal parts, including machine-gun conversion devices.

How the Mandate Would Work

The version reaching Newsom's desk is far narrower than the bill that first cleared the Assembly in May. The Senate stripped the original criminal misdemeanor for disabling the software, the $25,000-per-violation civil penalties, and the mandatory manufacturer self-attestation process after lawmakers and industry groups argued those provisions were technologically infeasible or overbroad.

What remains is a delayed, contingent mandate. Beginning no later than July 1, 2027, the California Department of Justice must check quarterly whether ASTM International has published industry standards for firearm-blocking technology on 3D printers. If ASTM issues qualifying standards, the DOJ 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.

Existing California Firearm Laws

California already prohibits unlicensed people from using a 3D printer or CNC mill to manufacture a firearm under Penal Code section 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.

Pushback From Multiple Sides

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. New York enacted a similar blocking-technology law earlier in 2026, and California modeled AB 2047 on that approach before making the mandate more conditional.

What Happens Next

Newsom has until the end of September to sign or veto the bill. Even if he signs it, 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.