California’s new bill requires DOJ-approved 3D printers that report on themselves targeting general-purpose machines.
Assembly Member Bauer-Kahan introduced AB-2047, the “California Firearm Printing Prevention Act,” on February 17th. The bill would ban the sale or transfer of any 3D printer in California unless it appears on a state-maintained roster of approved makes and models… certified by the Department of Justice as equipped with “firearm blocking technology.” Manufacturers would need to submit attestations for every make and model. The DOJ would publish a list. If your printer isn’t on the list by March 1, 2029, it can’t be sold. In addition, knowingly disabling or circumventing the blocking software is a misdemeanor.
We’ve been tracking this pattern. Washington State’s HB 2321 requires printers to include “blocking features” that can’t be defeated by users with “significant technical skill” (good luck with that on open-source firmware). New York’s budget bill S.9005 buries similar requirements in Part C, sweeping in CNC mills and anything capable of “subtractive manufacturing.” California’s version adds a certification bureaucracy on top: state-approved algorithms, state-approved software control processes, state-approved printer models, quarterly list updates, and civil penalties up to $25,000 per violation.
As Michael Weinberg wrote after the New York and Washington proposals dropped… accurately identifying gun parts from geometry alone is incredibly hard, desktop printers lack the processing power to run this kind of analysis, and the open-source firmware that runs most machines makes any blocking requirement trivially easy to bypass.
The Firearms Policy Coalition flagged AB-2047 on X, and the reactions tell you everything. Jon Lareau called it “stupidity on steroids,” pointing out that a simple spring-shaped part has no way of revealing its intended use. The Foundry put it plainly: “Regulating general-purpose machines is another. AB-2047 would require 3D printers to run state-approved surveillance software and criminalize modifying your own hardware.”
As we’ve said before on this blog, when we covered Washington and New York, it doesn’t matter if you’re pro or anti-gun. The state should prosecute people who make illegal thing, not add useless surveillance software on every tool in every classroom, library, and garage in the state. And as you can see, these bills spread – that’s how an small group can push legislation into the entire country. First, Washington proposed theirs, then New York, now California. Once those three states pass a law, that’s 20~25% of the country by GDP/population and thus every manufacturer is forced to comply with a bad decision in order to stay in business. If you’re a maker, educator, or manufacturer anywhere in the US, even outside these states, this is a problem-problem now.

USA, solving the problem in the worst way possible.

*California

You think Florida solves their problems in the RIGHT way?

Such freedom. Such bravery.

Reminds me of my friend and I discussing this open source printer that you build and maintain yourself.

"I wonder how the NSA will install the unique invisible tracking dots into the firmware?"

EDIT: Oops forgot the link

*Several states

Washington, for example, has a similar bill proposed.

*Inventing an excuse to impose draconian measures designed to crush competition to big business

Net York trying to get subtractive manufacturing CNC mills to obey this is going to be a trick.

The controller just runs Gcode for positioning and speeds. They'd need to preprocess the gcode through an AI database to check if the path builds a gun part shape then allow machining or block it.

Inevitably somebody will just replace the controller with a home grown system.

And a CNC mill can still run manual cuts a single passes that may not appear to look like a part, when done separately

This is old clueless men trying to make laws about technology they don't understand.

Blah blah blah. It's a stupid move because actual hardware is dumb. You apply a voltage and it moves. It will take 5 minutes to circumvent anything like that. Its probably already done. Meanwhile they get to see all your swivel joint dragons and every company's IP. No Company would want to ever use a 3D printer because its a lame IPn stealing funnel. Its a total security flaw. Meanwhile actual criminals will just circumvent all this.

I just don't really know how it's really going to work. Couldn't you just design your own parts with one weird bit of geometry and the computer wouldn't recognize it?

Like, I get you don't want ghost guns, but it seems like the bigger prize is going after illegal and currently legal guns that are actually used in mass shootings. 3D printed stuff seems like small potatoes compared to the daily casualty rates.

Remember that mass shooting the perpetrator used a printed gun? Yeah me neither.

Upholsterers have added leather handles. They, along with roofers have staple, nail and screw-guns themselves... Unlicensed! WTF LOL...

Imagine being happy with that?

Ethics and rights aside, this isn't even possible to comply with. The law applies to additive and subtractive manufacturing hardware, and expects it to automatically detect and refuse any attempts to manufacture a firearm. But that depends on an underlying assumption that a machine can answer the question "will this command (set) result in the construction of a gun?" And that assumption is false.

Even if you somehow designed an algorithm that could read a G-code program and determine whether it produces something shaped like a gun, it still wouldn't be enough - because the CNC machine is just one step of a manufacturing process. The human operator controls what materials and commands go into the machine, so they also have full control over all inputs that the "oversight" program is allowed to see.

Some simple ways to bypass this (hypothetical and perfect implementation):

• Print the gun in two pieces, then combine them manually.
• Print something that contains a gun, then cut out all the non-gun material.
• Use multiple separate machines for different parts of the gun.
• Design something that looks nothing like any existing gun, but is still capable of firing a bullet.
• Print most of a gun, the build the rest by hand.
• Build part of a gun, then print the rest onto the hand-made parts.
• Print part of a gun, then run a separate program to print the rest onto the previous result.
• A thousand variants of the above.

So even if this was something we wanted to enforce, it's just not possible. For the same reason why Minecraft abandoned their plans for an SMP "penis detector", this law could never be complied with because it's impossible to build a machine that actually meets the requirements.