Here is our VERY BRIEF summary
1): Ammo may only be purchased face to face from a licensed dealer. No internet purchases, no sales between friends, no shall not be infringed. The Government must approve your ammo.
2) If you have purchased a gun at your current address (handgun after 1996 or long gun after 2014) and you have a REAL ID or a Federal Limits Apply ID plus a passport or other proof of citizenship, you can pass an “eligibility check” in 2-3 minutes. These cost $1 every time you buy ammo, no limits on quantity or caliber.
3) If your ID address isn’t current or you don’t have a gun registered to you at your current address, you’ll have to do a regular ammo background check for $19, and the DOJ will take however long it wants to approve you (they haven’t said).
4) There are few exemptions for people who are not licensed 01/06/07/08 FFL’s. Curio & Relic licensees have NOT been exempted from the background check in the final published rules! This is directly from the DOJ.
Ammo purchase flowchart courtesy CA Rifle & Pistol Association