Traveler's Guide
Travelers Guide to the Firearms Laws of the Fifty States is published each January in both paperback and electrionic versions.
It can be ordered direct from the publisher online using link below for retail price.
US Concealed Carry Assn
United States Concealed Carry Association Concealed Carry Maps are updated regularly.
The link below will take you to the Oregon CHL map but you can check other states information by simply clicking on that state.
In addition to the map you can scroll down and glean much information about special characteristics of each state such as conditions on reciprocity. Some states do NOT require any permit but you must be of a certain age and otherwise permitted to own a gun.
California & Colorado
Colorado recognizes ONLY state permits when the other state recognizes Colorado's permit and then ONLY for resident permits.
Oregon does NOT recognize ANY other state's permits, therefore it is impossible to legally carry conceald there.
California barely recognizes it's own permits (CCW) and those are issued ONLY to CA residents on a "May Issue" basis. It depends on the county sheriff where you reside. NO non-resident permits issued.
Restricted Firemarms
There are some states, such as Californina that merely possessing certain types of firearms and/or magazines is a felony.
Just because it is legal to buy and own in Oregon does not mean you can even possess it in California.
Examples: AR style rifles with push button magazine releases
ANY magazines that hold more than 10 rounds of ammo