RCW 9.41.050
Carrying firearms.
(2)(a) A person shall not carry or place a loaded pistol in any vehicle unless the person has a license to carry a concealed pistol
Do not have a loaded pistol in a vehicle without a valid CPL.
there is no crime defined as "brandishing" in the WA RCW's
closest you will get is
http://apps.leg.wa.gov/rcw/default.aspx?cite=9.41.270 which is the one that gets discussed/argued a bit around here.
Link to the WA RCW's in general
http://apps.leg.wa.gov/rcw/default.aspx
Link to most firearm related RCW's
http://apps.leg.wa.gov/rcw/default.aspx?cite=9.41
tl,dr version
Get out and load unload and get in unless you have a valid WA CPL
No settled case law on a .270 violation, but there was a Yakima? incident which was dismissed as citizen was following the RCW's as above. BigDave or anyone else, do you remember the incident? Fellow outside a bank loading after getting out of his truck?