Quoted from WDNR
"Arms transportation:
• All firearms must be unloaded and completely enclosed within carrying cases designed
to carry a firearm when in or on any vehicle whether moving or stationary.
A holster is not a legal carrying case for a handgun in a vehicle unless it completely
encloses the handgun. All firearms must be unloaded when in or on any motor
driven boat while the motor is running.
Note: Firearms are considered unloaded if the shell or cartridge is removed from
the chamber of a firearm and any clip, magazine or cylinder attached to the firearm;
the cap is removed from a percussion muzzleloader; the flashpan is cleaned
of powder from a flint lock muzzleloader; or the powder and projectile is removed
from the barrel of an electronic ignition system muzzleloader."