What keeps people from buying ammo in neighboring states and just driving over?[\QUOTE]
Well that is illegal in CA, the ammo has to be shipped to a CA FFL who does the ammo eligibility check and you have to show up in person to sign the DROS, and then transport your ammo home. I can’t imagine what happens if you fail the ammo check, or if there is a comp glitch, since you probably can’t return the ammo.
Heck, what keeps someone from buying ammo legally (with the background check) and then using it in an illegal manner.
If you are a criminal, nothing will stop anything that is illegal. In CA all firearm ownership records are maintained by the CA DOJ Bureau of Firearms in their Automated Firearms System (AFS) and your DOJ BOF firearm ownership records in the AFS have to match up to your current address and drivers license to be able to buy ammo with a minimum $1 standard eligibility check. Otherwise you have to go with the $19 basic eligibility check every time you buy ammo. Not all ammo dealers do basic checks anyway.
If you haven’t bought a firearm within the last 5 years, but you bought firearms in CA, you have to go online to the AFS & update your ownership records to show what you currently own or decide you want to record what you own. If you moved within CA since you bought your firearm you have to go online & update your ownership records. If you move into the state with firearms you have to manually complete a New Resident Report of Firearm Ownership form & have it approved in the AFS. Oh and you need a REAL ID compliant drivers license to avoid having to take your passport or birth certificate every time you buy ammo. After that, everything is easy-peasey!