I'm probably not the only one that "climatizes" a blued gun that really needs shooting in the summer by bringing it out in a padded case, putting it on the porch rail, and unzipping a couple inches of the case so it can warm up slowly. Seems like the guns don't sweat much when they are handled this way. Of course, it goes without saying that humidity and storage in a padded case don't mix, but a case can help to avoid the cold sweats when going from a cool, indoor safe to a hot and humid shooting session outdoors.
