culcune,
1) Here is the specific, applicable stature (The United States Code, Title 18, Part I, Chapter 44, Section 926a):
"Notwithstanding any other provision of any law or any rule or regulation of a State or any political subdivision thereof, any person who is not otherwise prohibited by this chapter from transporting, shipping, or receiving a firearm shall be entitled to transport a firearm for any lawful purpose from any place where he may lawfully possess and carry such firearm to any other place where he may lawfully possess and carry such firearm if, during such transportation the firearm is unloaded, and neither the firearm nor any ammunition being transported is readily accessible or is directly accessible from the passenger compartment of such transporting vehicle: Provided, That in the case of a vehicle without a compartment separate from the driver’s compartment the firearm or ammunition shall be contained in a locked container other than the glove compartment or console."
2) Therefore, if: (a) you can legally posses these firearms in Arizona; and (b) you are transiting California for an Oregon destination; and (c) you can legally possess these firearms in Oregon; and (d) you fully comply with the entire "unloaded, locked container, separate container for ammunition, inaccessible to driver/passengers, etc." provisions of the aforecited United States Code Section, you should be on okay to drive through California.
PS: I do not mean to be critical, but I slightly resent your indicating “If this law is true”. It suggests that my prior post might be deceitful or erroneous.