The statement in this article regarding California restrictions is, IMO, too brief to convey what is “allowed” and required in California. Because of the length, my request for the following (Alt 1) was declined.

Alt 1 – “For example, in California, in most instances, ammo must be purchased, in person, thru an ammunition retailer in the state or, in person, thru a transfer agent in the state (an FFL or a licensed Ammunition Vendor). [“…a valid ammunition vendor license shall be required for any person, firm, corporation, or other business enterprise to sell more than 500 rounds of ammunition in any 30-day period.] It is illegal to purchase ammo out of state and bring it in yourself. Ammo purchased online (from within or outside the state) is shipped to an “agent” who in turn transfers it to you. [Regrettably many FFLs will not do transfers – unacceptable time and effort – and there is a fee for the transfer (of course) which some “agents” have jacked up well over what is prescribed.] If you have not purchased a firearm in California within a few years of the ammo purchase date, an “eligibility check” is required (plus the associated processing fee…and delay of unspecified length). You can purchase a firearm and ammo at the same time and both sales will be processed based on approval of the firearm sale. [This is NOT a comprehensive description of the hoops you might need to go thru or part of which you might avoid.]”

Alt 2 – “For example, in California, a licensed transfer agent is required, possibly a delay in actually taking possession, and, of course, a fee – too lengthy a discussion for this article. See https://oag.ca.gov/firearms.”