The LEO hiring requirements have been dumbed down quite a bit.From a legal standpoint...
You can enter WA with an "assault weapon" as long as you leave with it. You cannot move here with it. You can possess it here, however you can't leave it here, sell it here, etc it must go back home with you. Same with your magazines. Can bring them in, can use and possess them here, so long as you leave with the same amount you brought in.
Also, just FYI your statement of them being locked in a different container is false. You can have an unloaded rifle in your car in washington with a loaded magazine right next to it. WA defines loaded as (when referring to a firearm with a detachable magazine) as magazine being inserted into the weapon. A loaded magazine next to your AR15 in your car is not to be construed as loaded.
That being said..........
Some idiot cop or sheriff may interpret the law any way he pleases and leave it up to a judge.
I just got done arguing not 2 days ago with a sheriff at an especially fuddy LGS in clark county (name will be left out) about how 30 round magazines are not allowed for anyone who isn't law enforcement. I explained to him multiple times that we can possess them, we just cannot import them. I explained to him that the burden is on the seller only and possession is not banned for WA residents. He boldly argued with me that it was illegal for me to carry my pistol with more than a 10 round magazine. And this guy pulls people over for a living.
So.... tread lightly and don't run any stop lights. You'll be fine
This guy is why you want nothing to do with them.
When only bad cops are left...