Dave - that brings back another memory = when hunting in minus 20 to minus 50 degrees F on the Primitive Weapons moose hunt, if the rifle had not been discharged, it was left leaning against a tree outside the tent/dwelling - sometimes with a tarp over it to prevent an even frosting by morning. That way no moisture due to condensation was introduced into the bore or ignition channel that can easily cause a misfire or hangfire when the time came to kill a moose.
If the gun had been fired, it was brought inside, barrel removed and cleaned in a container of water.