>relatively simple mill/lathe/tapping setup

To be honest, as someone familiar mostly with computers, I have no idea where to start with this and it sounds a bit intimidating. Buying a 3D printer and using some 3rd party design sound very easy in comparison.

You're certainly right that it's possible for someone determined to make their own firearm, but raising the bar still has immense value.

Tradeoffs between freedom and safety are another, unrelated discussion.

The easier a thing is to do, the more often people will do it. And downloading a file and pressing print is a far, far lower barrier than machining steel.

What do you mean by regulation? Laws that could lead to a fine or jail time, or the enforcement of laws through ie. the police?

Non-commercial projects and individuals can do bad stuff too.

I agree the bar is a lot higher for those projects than massive corporations, but I think it's a pretty arguable case that "people are using 3D printers to make guns with features that would otherwise be illegal, and they are being used in crimes in some number" clears that bar.

Individuals can do a lot of bad stuff too? "Mark Zuckerberg" is still an individual.

> making it illegal to possess DIY guns is not enough.

This would be an unconstitutional law, per Bruen.

Ah, I think I know this one. It's because people who make their own guns are nerds. You know, like you or I, except in a different topic. I remember reading a couple of posts on R*dd*t where two folk were discussing fitting accessories to guns and one posted something like "No, you can fit that, all you do is mill a slot on top of the receiver and drill and tap a hole at the end and you can just about screw this thing in place" kind of thing.

I read the discussion and thought "yeah that's nerd talk, just not about analogue synthesizers, old Landrover gearboxes, or Pascal compilers".

I guess the reason for blocking 3D printers from making gun parts is because it's easier than doing it "by hand". All you really need to do is get a copy of the files from someone who has them, print it out in something suitable, and you have viable gun components with very little "real work" involved.

By contrast here in the UK, where it's quite surprising what you're allowed to own and operate if you comply with the laws (here you're allowed fully automatic weapons, if you keep them at a suitable shooting range and don't try to wander around town with them, and you're not oh maybe a convicted violent criminal for example) one of my late father's friends was a gunsmith. My dad was an excellent machinist, and so he made some components for his friend, and I remember standing in the machine shop where they worked while he turned a chamber for a gun his colleague was building in the lathe. "There you go," he said, taking it out of the chuck, "that's legal".

Then he took it over to the mill, and cut a couple of holes and slots that would allow it to actually function as a chamber, "And there - now it's *illegal*."

Then, as he handed it to his friend, who was licensed to have "home made" gun parts, to stamp his initials on, "And now it's legal again."

Of course since people aren't allowed to just walk around with handguns since the school shooting, it's all a little more difficult - but the police will tell you what you need to do to keep it legal.

It's still slightly easier to get a shotgun licence than a motorcycle licence here.

The obvious answer is to slice up your gun model into a number of sub-parts which individually aren't detected by the algorithm but collectively still form a functioning gun. And there's an unlimited number of ways to slice up a model, so it is impossible to create an algorithm which catches everything.

What's next, keep track of all printed parts and invent the math to recombine them in every way possible to see if it could form a gun? Trivially defeated by using multiple printers. Hmmm, sounds like a good reason to force everyone to register their 3D printer with their real identity, and only allow a print after the model has been uploaded to the Federal Printing Database for verification...

Ah, but don't you see? Something Must Be Done, and "gun part detection" is, indeed, Something. (ignoring that it fails the "thing" part of the definition, because it can't possibly exist)

Still took a bit of effort and lateral thinking to hit 1,00,000 rounds per minute.

> ... why aren't we seeing European countries mass-banning 3D printers?

Dunno, because most europeans are way more responsible with their guns than many people in the US?

For example in the EU (and in Switzerland) before you can buy a gun, you get specific training about safe and responsible handling. And in many countries the cops shall come to your place and verify that you've got a gun safe and a separate safe for the ammo.

And we don't offer AR-15 to our kids when they turn 14 y/o (well I say that but my daughter wants to shoot my weapons and, once she turns 14, she can switch from air rifles to the real thing as long as she's accompanied).

Just to be clear: we have shitloads of guns and ammos in Europe. There's even one EU country with concealed carry. I think it's estimated there are twice as many non-registered weapons as registered ones. We've got big guns factories and gun brands in the EU. And there are millions of illegal full-auto weapons like kalashnikovs (well Zastava M70, which is the same) from the war in Yougoslavia in the hands of criminals. And shitloads of fully functional weapons, including handguns, from WWII circulating.

In my native city (Brussels, Belgium), at the moment there are drug dealers firing kalashnikov on police stations regularly (it's a big issue, it's in the news daily and the authorities don't know what to do).

In addition to people shooting at the range (and, sadly, to drug dealers/criminals ruining our cities), we've got lots of hunters too.

Many people at my shooting range have their official gun transport license full (that is 30 weapons) and some have more than 100 weapons in their collection.

It's a fantasy that europeans don't have guns: we're (mostly) responsible with them.

It's maybe because we're responsible with our guns that the EU hasn't banned 3D printers... Yet (it's the EU, so nothing is unthinkable).