Traveling with Firearms in California
California Penal Code section 12025 does not prevent a citizen of the United States over 18 years of age who is not lawfully prohibited from firearm possession, and who resides or is temporarily in California, from transporting by motor vehicle any pistol, revolver, or other firearm capable of being concealed upon the person provided the firearm is unloaded and stored in a locked container.
The term "locked container" means a secure container which is fully enclosed and locked by a padlock, key lock, combination lock, or similar locking device. This includes the trunk of a motor vehicle, but does not include the utility or glove compartment. For more information, refer to California Penal Code Section 12026.1.
Careful with the large cap mags. I'm looking for som info but to be safe buy some 10 rounders. Disassemble the high cap mags when in CA. Possession is a non issue IF you possessed the high caps in ca before the ban. IF you did not it could be considered importing. It's stupid and would almost be impossible to prove in court. BUT you want an easy time so play nice. Look here.
This is my carry setup.