People who assemble their own guns in California have to apply for a serial number to affix to the gun. Otherwise, it is still legal to buy gun parts and assemble them without a background check. However, federal law may soon require that gun parts have their own serial numbers, and for people to have to pass background checks in order to purchase gun parts.
M., D. (2022, March 27). California gun laws 2022 – your top 12 questions answered. Shouse Law Group. Retrieved May 4, 2022, from https://www.shouselaw.com/ca/defense/gun-laws/