Actually, there are high rates of gun ownership and sales even in states such as California (here’s a report stored in the Internet Archive about sales in 2023-24, California is third). Additionally, as shown in our state’s own 2024 Crime Guns seizure report, the amount of people willing to use privately made firearms (or acquire firearms outside of official designated pathways) is not insubstantial.

(Also for the record, you are able to assemble a privately made firearm in the state of California for personal use. You may have to store it in a safe and take safety classes if you plan on declaring it, but it is possible and can be legally performed.)