I wanted to expound on my previous point a little bit.
Yes, homemade firearms have gotten a lot easier to make in the last couple years. The advent of better plastics (and their use in firearms engineering) as well as the proliferation of hobby grade manufacturing equipment (mostly Chinese lathes and mills, along with 3D printers and cheap CNC) have spawned a loose community of people that are really pushing the boundaries on home, cheap gunsmithing. (It's not a group really, more of an
idea ) Yes, absolutely, criminals are using these kits to get "around" US (and CA) gun control laws. And that's kind of the point. CA or the ATF can make it harder for folks to build these legally by requiring FFL checks on a slightly less machined hunk, or making us put serial numbers on them, or whatever else they come up with. (CA's next step is probably trying to regulate barrels and bolts) but the criminals aren't going to care. And the kits are a market driven intermediate step. A step between "you must buy a complete gun to get one that works" and "You can build a complete working gun easily at home". The first steps away from kits have already been made, both here and overseas, so really the AG is about 18 months* behind where he thinks he is right now.
Gun Control, as CA wishes it, is dead. It has become technically impossible to keep someone that wants a semi-auto firearm from building one easily. They just haven't figured it out yet. Australia is realizing it this summer, and low key freaking out. I've also seen some folks out of China making noises about realizing what can be done now.
Additionally, CA isn't doing them or the ATF any favors by dragging the definition of "firearm receiver" into court.
Firearm frame or receiver. That part of a firearm which provides housing for the hammer, bolt or breechblock, and firing mechanism, and which is usually threaded at its forward portion to receive the barrel.
Would anyone like to tell me which part of an AR houses the hammer, bolt or breechblock,
and firing mechanism? Or which part of a Glock? Or 1911? Or MAC-10?
FWIW the "easiest" ghost gun kit I am currently aware of is the various Glock 80% kits (Polymer80 is the most common). Those can legitimately be completed with a cordless drill and a sharp hobby knife in an hour or so. Easier than some Ikea stuff.
*Maybe farther behind actually, as folks are already beta testing ammo with 3D printed cases and homemade smokeless powder. So we will get them on the next step as well.