Has to go Common Carrier rather than USPS if it is not FFL to FFL.
If it is FFL to FFL it can go USPS in a flat rate box much cheaper than the others.
Problem though is that FFLs must be registered with CA before they can do business with a CA FFL.
Anyone can legally ship a handgun to an FFL in CA, just FFLs have to be on CA's list...
