Actually ammo reloaded at home shoots better than factory ammo this is a known occurance. And guns put together with kits usually shoot better and have less problems than mass produced factory ones.

Guns aren't really that difficult to make. Hell that Japanese guy shot Shinto Abe with a gun he made himself although bit of a different thing because it used a battery to ignite the gunpowder but still the same idea.

Making guns isn't hard to do.

3d printed ones are a joke though. You can only use them a few times before they become even more dangerous and unpredictable. Anyone who wanted to use an actual firearm would never use a 3d printed gun.

Maybe one of those 200K metal 3d printers or whatever. But at that point it would be easier to machine the parts yourself out of metal. It really isn't as difficult as you seem to think it is to do that.

If they wanted gun control (which California already has a bit more of than other States) then they could pass a law doing that. This is 100% a surveillance law.