After reading about your "bad Day" I still feel believe that any day out hunting is far from being a bad day. There are a few lessons learned here that you could apply to future hunts in "extreme" weather. One is to put a small piece of electrical tape over the end of your muzzle. This will not affect the departing bullet but will keep water, snow, dirt, and all out, preventing your powder from getting wet from that end. As far as the reciever, I've seen cut plastic bags or sarran wrap put around any possible openings to prevent water from entering. When in doubt about the powder charge, find a dry spot like an overhang or thick tree and pull the bullet and reload.
Last year opening day rifle here in NY brought heavy rain all day long. We all managed to hunt all day with no deer seen but had a great time. You should have seen the local laundry mat that evening. Best of luck on future hunts!