I only use one gun in wet/snowy weather, a 35 rem lever action. I own it about 35 years and have used it many times in wet weather. The past 10 years or so the buttstock finish looked a little faded and flaked, so I decided to refinish all of the wood. I often wondered how the magazine tube and barrel was going to look under the forearm since I never took the forearm off in all those years. Surprisingly, theres wasnt a bad case of rust under the forearm. In fact, that metal was probably in better shape than the exposed metal parts. When I got back from hunting in wet weather I always dried and lightly oiled the rifle, then put it next to a heat source, to completely dry it out. I had never removed the barrel band and forearm. The tight fit, metal and wood finish and barrel band must have alot to do with what I found.
I have always taken the forearm off my bolt actions when wet weather surprised me while out hunting, just to make sure I didn't end up with a bad case of rust. I always had at least one back-up rifle ready to go out. Sighting in the rifle after taking it apart is probably necessary, even if it's only one shot. IMO.