Ammunition or Loaded Magazines in locked containers
Ammunition may be carried in the same container as the gun – loose ammunition or ammunition in ammo boxes does not make a gun loaded, because the ammunition is NOT “placed into a position from which it can be fired”.
You may transport loaded magazines and speed loaders, so long as they are not inserted into the magazine well or cylinder of the firearm. That does not make a gun loaded, because the ammunition carried that way is NOT “placed into a position from which it can be fired”.
A loaded magazine is not the same as a loaded weapon, and possession of a weapon and a loaded magazine for that weapon does not, necessarily, mean you have a loaded weapon.
Anyone who asserts something contrary to the above 3 points is simply wrong. That does not mean you cannot be arrested by uninformed or badly trained law enforcement officer, or charged with the crime of carrying a loaded weapon by an uninformed or politically motivated prosecutor. It does mean that, if it goes to court and you have good representation, the prosecution should lose on the law. There are certain exceptions to this outlined below.
Your comfort level may lead you to do more than the law requires. Please also see Transport Restriction for Handguns for some important additional notes on transporting handguns in California.