Anyways, literally the first sentence of the article is false[1]. Self-made firearms in California are required to have a serial number, must be put into the state registry (a somewhat byzantine process), and are illegal to resell[2]. In other words, the gun is either legal OR untraceable. It can't be both at the same time.
[1]: https://oag.ca.gov/system/files/attachments/press-docs/consu...
[2]: For ones manufactured after 2018, your family can't even inherit them when you die— they have to be surrendered to the police for destruction. If you have a relative you really don't like, you should definitely bequeath them your homemade guns— there's a non-zero chance they'll end up in prison for possession.
I'm a writer. I'm dirt poor. I can't get adequate funding for my blogs. When I complain about my poverty, I get told to "get a real job." When I point out the rise of the Gig Economy and the fact that we have worse income inequality than in The Gilded Age, people mumble some other bullshit excuse and refuse to hear that these supposed (well paid) "real jobs" are in rather short supply, so, no, it's not laziness on my part.
It's a broken model. If we want quality writing, we need to find some way to pay writers for their work so they can fact check and spell check etc.
In California you need the state DOJ's permission to mill an 80% lower, then they give you a serial number that you have to engrave on it within 10 days.
Other states have different laws. Some are similar to CA but most are less restrictive. There are places where it is true to say that "Such firearms have no serial numbers, and ... legally bypass background checks and registration regulations." But the author is conflating the national laws with the laws for manufacturing in California (without mentioning that what happened in California is actually multiple felonies). It's either ignorant, unintentionally misleading, or pushing a narrative.
I believe OP is right, though I’m not a resident of CA: you can have a non-functional piece of metal or a registered functional “firearm” (which the feds say is the lower). A functional, unregistered lower would be against CA law.
In other states, like neighboring AZ, there’s no issue purchasing an unregistered, non-functional lower, finishing it into a functional piece, and then using it for private use (including non-commercial sale).
I'm not sure what can be done about this, ultimately, short of turning society in to a completely totalitarian surveillance state where everyone's actions are fully monitored and controlled by the state and there is effectively no privacy.
Those who are trying to control technology are fighting a losing battle.
However, there is a vast difference between having to fire up a lathe and machine a barrel vs putting together a kit of a half-dozen or so primary parts.
By analogy, most people can put together a computer. Only a very few can actually design and manufacture a motherboard even though it is relatively cheap to do so nowadays.
In addition, most people who are going to go on a shooting rampage probably don't have the skills to operate a lathe or milling machine.
This stuff isn’t rocket science.
"Infringed" can certainly be read as any process that gets in the way of gun purchasing.