1. United States
2. Calif.
3. Letter

I am writing to urge you to oppose AB 2047, the California Firearm Printing Prevention Act, which passed the Assembly 58-19 and now moves to the Senate. The concern motivating this bill is real. Recoveries of 3D-printed crime guns have risen sharply, and the Legislature is right to treat that seriously. But AB 2047 addresses that problem by mandating technology that does not exist and cannot be built as described. The bill requires printers to evaluate STL and CAD files using a “firearm blueprint detection algorithm.” But 3D printers do not interpret geometry: they execute G-code, a sequence of coordinates and movement instructions. No algorithm running on consumer hardware can reliably distinguish a firearm part from a bracket, tube, or housing based on that data. The bill’s own technical framing describes something with no working implementation anywhere. To attempt compliance, manufacturers would need persistent file-scanning systems in every printer sold: surveillance infrastructure with no guardrail limiting it to firearms. The EFF has documented that this replicates the anti-consumer lock-in of 2D printer ink DRM, concentrating market power among large incumbents while eliminating smaller manufacturers and open-source firmware like Marlin and Klipper. Colorado’s HB26-1144 took the opposite approach, targeting people who knowingly manufacture prohibited items rather than the tools they use. That is enforceable. This is not. I urge you to: • Vote no on AB 2047. • Request an independent technical feasibility review before any Senate vote. • Explore conduct-based alternatives modeled on Colorado’s HB26-1144. • Protect California’s maker and education communities from a compliance regime that cannot achieve its stated goal.