Discussion

California ghost-gun bill wants 3D printers to play cop, EFF says

asdff: Why don't these bills go after ammo or gunpowder access? Seems as long as you have access to a cylinder, and ammunition, you can make a gun.

alterom: It's ridiculous that this is even being discussed. The people proposing the bill must have zero understanding of how a 3D printer works.It makes as much sense as requiring saw manufacturers to implement protections that restrict what can be cut out with a saw.Or pen manufacturers being required to enforce copyright.Any form of this bill will 100% fail to attain its stated objective, while having horrendous not-quite-unintended consequences.And in the end, what's to stop someone from assembling an unlicensed 3D printer to make unlicensed prints? That's how the industry literally began.(Not to mention: what do they think would happen to the hundreds of millions of existing "dumb" 3D printers? They won't disappear because there's a law).Sigh.

maininformer: A. What if some part looks like some other non-gun part? B. What if they can further break down the pieces to avoid detection?

dabluecaboose: > Any form of this bill will 100% fail to attain its stated objective, while having horrendous not-quite-unintended consequences.California gun laws in a nutshell.

teaearlgraycold: California laws in a nutshell.

dlev_pika: AFAIK If I scan a dollar bill, both the hardware and the software won’t let me be.How is this different?

simplyluke: The 3d printer gun legislation has been rearing its head in a bunch of states this year, and generally with very similar patterns. I suspect some of the pro-gun-control groups have been pushing it to lawmakers given most legislation is basically copy-pastes from lobbying groups at both the state and federal level. Colorado, Washington, New York, and now California have all floated legislation attempting to make device-level restrictions around the issue. I only followed Washington's in depth, and they ended up removing all the requirements on manufactures, but did criminalize possession of files which I suspect won't hold up to a first amendment challenge.

ginkgotree: I'm so glad I left California 6 years ago. They are going to regulate and tax their startups and innovators away to other states. This is supremely stupid.

nradov: This is the inevitable result of having a single-party government which is no longer accountable to regular citizens.

dlev_pika: laughs in Texan and the entirety of the South

jmyeet: I'm surprised the EFF didn't address the issue that traditional printer manufacturers already comply with law enforcement, specifically that a fingerprint of yellow tracking dots [1] are printed and printers will often refuse to or fail to copy images of money.My point is there's already precedent for printers cooperating with authorities so one can see this as simply an extension to 3D printer manufacturers.I suspect it's a losing battle for the EFF and 3D printer manufacturers to resist some kind of fingerprinting or even the prohibition of things that are guns.I'm not saying that's right or wrong. That's just what I expect to happen. And if you want to argue against it, you should address the printer tracking dot issue or argue how this is different.[1]: https://en.wikipedia.org/wiki/Printer_tracking_dots

rolph: [delayed]

horsawlarway: Personally, I see this as an assault on 3d printing more than any real attempt to regulate guns.I own several 3d printers. If I wanted to make something resembling a firearm I'd go to home depot WAY before I bothered 3d printing parts. You basically just need a metal tube, and well... a pipe from home depot does that much better than trying to 3d print something much less reliable.So given we don't do this regulation for any of the much more reliable ways to create unregistered firearms... what's special about 3d printers?So my assumption is immediately that some relatively large lobbying group feels threatened by 3d printing, and is using this as a driver to try to control access and limit business impact.Either way, this is bad legislation.

tempaccount5050: Not that I support any of these obviously stupid bills but:> what's special about 3d printers?They can make guns made out of plastic and metal detectors are kind of the primary way we try to find guns on people.You are probably right about the lobbying group, I agree.

15155: > metal detectors are kind of the primary way we try to find guns on peopleWhat are bullets and shell casings made out of again?

captaincrisp: And importantly the barrel. Plastic cannot contain the pressure required to fire a bullet.

Retr0id: One practical difference is that you can make dollar bill detection relatively robust. Sure, you could cut it into 4 pieces and scan them separately, but you'd still get stuck when it comes time to print them. There are only finitely many dollar bill shapes. But there are infinitely many plausible gun components, and infinitely more ways to divide them into sub-assemblies.

EvanAnderson: It would be interesting to test what the minimum detectable piece of US currency is. (I wouldn't want to do it on a network-connected system, though.)

NoMoreNicksLeft: There is a pattern of yellow dots on the currency. I do not know at what size they tile across the paper, but the piece of currency would have to be smaller than that, most likely.Far easier to dump the firmware and NOOP out that algo.

Kirby64: More importantly, what is the barrel made out of? Yes, I know there’s some fully printed guns… but my understanding is that those are basically 1-time use and even then it’s questionable how reliable that single use actually is…If you want something resembling an actual gun (more than one shot, won’t blow up in your hand, some reasonable chance of accuracy, etc), then you’re going to be using multiple metal components (including the bullets of course) all of which would show up on a metal detector.

mothballed: Black powder guns, at least ones of antique design (but modern production), are federally ~unregulated already anyways. A 6 year old in North Dakota could order one mailed right now to his house, no background checks, right off the internet -- legally.There is also the "felon carry" as its called late 19th century black powder percussion pistols, you can also order off the internet, regardless of criminal history and with no scrutiny of the chain of custody.

MisterTea: I really think all of this is the result of Mangione. Regulating 3D printers has been talked about for years with no action. Then a year after the CEO of a large well known company is killed with a 3D printed gun the states are suddenly pushing highly invasive 3D printing laws. It's no coincidence NY was the first to push for such a law, the state where said CEO was killed.

rolph: whats special is speed and consistency.when you manufacture a personal firearm, it is supposed to be yours, for your use. the 3d printer aspect, makes it possible for a group to print large quantities of receivers, under the radar, to be combined with "accesory parts" close to "drop-in" assembly style.

trollbridge: At issue here is that anyone can build a 3D printer. There's one in my basement a hobbyist built entirely from easily-sourced parts, and the controller is entirely open source. It never phones home and isn't really connected directly to the Internet at all.

GenerocUsername: Careful. Or they will try to regulate ghost printers.

horsawlarway: > They can make guns made out of plasticSo can many, many other things. Hell - something like this will do SO MUCH BETTER than anything I can print:https://www.mcmaster.com/products/pipe/carbon-fiber-1~/?s=pl...It's weird because 3d printed plastic is WAY down the list of things I'd prefer to trust handling the explosion from ammunition.Frankly - even the hobbyist CNC I have is a MUCH better method of creating a plastic gun. FDM printing is not something I'd want to trust in this case, neither is SLA printing in most materials (some of the very high end ones like nylon in a formlabs printer... maybe?).But my point stands - guns aren't that hard to make, and we aren't trying this legislation with any of the other myriad manufacturing methods. Hell - compare to a potato cannon... (also a plastic gun, btw...)So what's different about 3d printers?My hunch is this has fuck-all to do with guns, and a lot to do with something else, because 3d printers ARE different in that they let me manufacturer all sorts of other, much more complex, goods much more easily and cheaply at home.

MisterTea: > The primary goal is clear and simple: to require 3D printer manufacturers to use a state-certified algorithm that checks digital design files for firearm components and blocks print jobs that would produce prohibited parts."state-certified algorithm" has a really nice tyrannic ring to it. I am sure once this has passed the rich people can finally sleep at night knowing they are safe from roving gangs of armed Mangiones.

qurren: A 3D printer, at least of the Prusa variety, is really just a bunch of stepper motors and a dumb motor driver executing a series of effectively "rotate by X steps" commands, which is what the gcode file is. It doesn't know what it's printing. It doesn't even know that it's a printer.If they wanted a gate on designs it would have to happen in slicing software, not the actual printer.

MisterTea: Indeed. I grew up in a a machine shop than ran both manual and CNC machines and spent my summers in from of mills and lathes running jobs. I now do industrial automation and machine repair. With that being said, yeah, no way will this work. Ever.And software? My Bridgeport and Logan were built before computers were available to the home consumer. Good luck stopping someone like me.

subhobroto: I don't understand the problem solving mindset that thinks banning guns would solve the problem of a person intent on causing harm.In the U.K., where I feel guns are only showpieces (do even cops have them?), stabbing is a known problem.In India, where ammo is way more expensive than machetes and knives, people are literally murdered with them.The only argument I can understand, when it comes to banning guns, is that it reduces the blast radius that an evil person can have.So what's next, lock down the air, radio, roads, internet, water, food supply chains because these are all attack vectors?If that's the proposal, what's my plan when coyotes and mountain lions attack my child and I on our regular walks on rural property?

cultofmetatron: guns democratize mass murder. With a gun, I can kill a bunch of people before police can stop me. A knife? At best I can kill one or two in a public place before people run away and eventually a different group is going to stop me pretty quickly.

dole: Killers are going to kill. Guns don't democratize it, just makes it easier. Maybe at best YOU could kill one or two:https://www.cnn.com/2024/11/16/china/china-stabbing-yixing-c... (8 stabbed to death) https://en.wikipedia.org/wiki/Chenpeng_Village_Primary_Schoo... (1 killed, 24 injured)So they should stop you from 3d-printing knives too.

hypeatei: > any real attempt to regulate gunsAny real attempt would need to be at the national level, not that I would advocate for it, but it's simply a pipe dream to create a "gun free zone" in a country with 100s of millions of firearms. There are plenty of gun enthusiasts in California, they just don't flaunt it or talk about it.

tylerflick: I used to work in this industry and can confirm. California was by far the biggest cohort of consumers we had.

subhobroto: - can you build bombs to blow up an apartment complex full of 1000s of people?- can you poison the water supply of an apartment complex full of 1000s of people?- can you drop a harmful substance using a $50 drone onto an open area where of 1000s of people have congregated?

nemomarx: We also restrict the components of those pretty heavily, though. Try buying too much fertilizer without a farm and see who shows up.This isn't a judgement on your general point, but I think bombs and bioweapons and etc are very bad examples for you here.

antonymoose: The “Oklahoma City Fertilizer Bomb” style bomb is heavily watched. ANFO just isn’t a good vector for a lone wolf anymore. With that said, any GWOT veteran with explosives training could make enough HME to make a mass casualty event à la OKC all over again. Maybe not all at once, right this second, but it’s a real threat vector. Worse, these training manuals available open-source and easy to replicate.My neighbor is retired EOD, he has all Federal licenses manufactures explosives for the purpose of stump removal, if you can believe it, I’ve seen the process. It’s so easy a caveman could do it. Thankfully, no one really seems to do so. Mostly because manufactured firearms are easier to get ahold of. Or in Europe, smuggled weapons.We cannot forget what insurgents in Iraq and Afghanistan did. It’s hubris to say “can’t happen here.”

cjbgkagh: While quasi regulated they just raise the bar of expertise required. Poisons, bioweapons, and explosives are pretty easy to make at scale without using suspicious inputs.

krunck: Lets imagine a similar situation but instead of with an additive manufacturing process they try to regulate a subtractive manufacturing process: a traditional CNC machine. There is no way to prevent the CNC system from machining gun parts as along as the machining is done in discrete steps with the same work piece. The software can't know what sitting on the CNC table.In additive manufacturing it is more difficult but not impossible to print a bunch of pieces that look nothing like a gun part but and in the end be assembled into a gun.In both the above cases there would need to be sophisticated surveillance software to even come close to detecting "gun-ness."While I don't have a horse in the gun control race, I do have one in the open-source, running a local OS, running what software I want, and controlling what that software does races.

15155: WA state's legislation includes subtractive methods, CA's omits it so that they don't have to deal with the wrath of Haas.

aidenn0: Omitting subtractive methods makes it rather toothless, since there have been places you can go to push a button to start a mill making you a receiver (which is the part that is considered "the gun" to address ship-of-theseus questions aboug guns), then you can add the other parts yourself.

15155: I believe these events/places where folks were pressing a button to go from billet to receiver were shut down by BATFE some years ago (see ATF Ruling 2015-1 - https://www.atf.gov/media/19161/download)> An FFL or unlicensed machine shop may also desire to make available its machinery (e.g., a computer numeric control or "CNC" machine), tools, or equipment to individuals who bring in raw materials, blanks, unfinished frames or receivers and/or other firearm parts for the purpose of creating operable firearms. Under the instruction or supervision of the FFL or unlicensed machine shop, the customers would initiate and/or manipulate the machinery, tools, or equipment to complete the frame or receiver, or entire weapon. The FFL or unlicensed machine shop would typically charge a fee for such activity, or receive some other form of compensation or benefit. This activity may occur either at a fixed premises, such as a machine shop, or a temporary location, such as a gun show or event.> A business (including an association or society) may not avoid the manufacturing license, marking, and recordkeeping requirements under the GCA simply by allowing individuals to initiate or manipulate a CNC machine, or to use machinery, tools, or equipment under its dominion or control to perform manufacturing processes on blanks, unfinished frames or receivers, or incomplete weapons. In these cases, the business controls access to, and use of, its machinery, tools, and equipment. Following manufacture, the business "distributes" a firearm when it returns or otherwise disposes a finished frame or receiver, or complete weapon to its customer. Such individuals or entities are, therefore, "engaged in the business" of manufacturing firearms even though unlicensed individuals may have assisted them in the manufacturing process.

codedokode: Sorry if it is a dumb question, but why in USA people try to regulate 3D printing instead of banning sale of bullets without a firearm owner license? What stops people from buying Chinese printers or components on AliExpress? Or using an open source printer? At the same time, if you cannot buy bullets, your plastic gun is worthless.

giancarlostoro: The only thing you need to make is the "lower" or whichever part the ATF constitutes as "the firearm" I've seen someone take a shovel and turn it into an AK. Once you have the "firearm" part of whatever gun you're building, the rest of the parts can be shipped to you in most of the country (idk about CA, and NY though) and you can easily assemble the rest of the gun.Like you say, you just need to build a key metal piece, and voila, the rest is buying parts that can be delivered to you, in some cases fully assembled.You could also just buy black powder guns directly to your home (idk about in CA or NY though) which are not treated as "firearms" by the ATF.The only people shooting 3D printed guns are enthusiasts usually, who have other guns.

horsawlarway: Cool - you mean like the CNC I have sitting next to the printers? Which this legislation doesn't cover?So no - not buying it. Hell, there's not even a real price difference. I can get a Nomad3 from Carbide 3D for the same approximate cost as an H2D from bambu labs.And I can get super cheap temu versions of either for under 500.

doublerabbit: Next up flinging rubber bands with your two fingers to be banned.

favorited: > You basically just need a metal tube, and well... a pipe from home depot does that much better than trying to 3d print something much less reliable.Why would you buy a pipe at Home Depot? A gun barrel is not a firearm, and is not required to be registered or serialized. You can drive to Arizona or Nevada and buy an actual barrel, with rifling, manufactured to meet well-known specifications, without showing an ID. Until this year, you could have a barrel shipped to your California residence without an ID. There's no need to build the Shinzo Abe contraption.> So my assumption is immediately that some relatively large lobbying group feels threatened by 3d printing, and is using this as a driver to try to control access and limit business impact.Occam's razor. This isn't a shadowy manufacturing cabal, threatened by 3D printing. Gun control lobbyists are trying to prevent the printing of handgun frames and Glock switches, because they're the easiest parts to print.> Either way, this is bad legislation.California legislators haven't met a bad gun law that they don't like.

mothballed: I don't think the licenses are hard to get anyway. The hardest part is satisfying the storage requirements.As a bit of trivia, when congress defunded the ability for felons to restore their firearm rights, they actually forgot part of it. By an accident of history, felons can still get an explosives license.

rolph: [delayed]

dmoy: > but why in USA people try to regulate 3D printing instead of banning sale of bullets without a firearm owner licenseI mean we're talking about CA, so they kinda already tried to do thathttps://giffords.org/lawcenter/state-laws/ammunition-regulat...But, it may not be constitutional:https://calmatters.org/justice/2025/07/gun-law-ammunition-ba...So the real reason is that the ultimate law on the books on gun regulation was written by a band of, you know, armed revolutionaries, who were pretty big fans of the whole armed revolution-ing thing. And it still hasn't been amended.I bet if you went with a simple majority vote today, you wouldn't get the 2nd amendment. But amendments are pretty difficult to pass, much higher requirements than a simple majority.

bdcravens: I've always felt that it you want to really impact gun violence, tax the hell out of ammo and gunpowder. Like $20/bullet. For those who believe in self-defense, a handful of bullets is all you need your entire life, and ideally they'll go unused.Could probably create exceptions for bullets used at the gun range, so you can become proficient and safe.Tricky part would be hunting, but restricting such a tax to ammo used for handguns is probably an 80% solution.

akersten: > Could probably create exceptions for bullets used at the gun range, so you can become proficient and safe.Amusing to imagine the red diesel of sport shooting - better hope the tax authority doesn't find any combustion-proof dye on the self-defense shell casings!

bdcravens: To be honest I was thinking more along the lines of you either store ammo at the range, with a checkin/checkout process, or you can receive a tax receipt for number of spent casings.

burnt_toast: > Cool - you mean like the CNC I have sitting next to the printers? Which this legislation doesn't cover?Other states like Colorado have similar bills that define a "3d printer" as a computer aided machine that uses additive or subtractive manufacturing processes so CNC machines likely aren't safe either.https://leg.colorado.gov/bills/hb26-1144

ChrisArchitect: Source: https://www.eff.org/deeplinks/2026/04/dangers-californias-le... (https://news.ycombinator.com/item?id=47759420)

tomhow: Comments moved thither. Thanks!