Before throwing it out a couple of months ago, a Dunhill Shell zulu was my beater/yard work/rain pipe. I've got an MM 5th Avenue Diplomat for that now. It just smokes better.
When I lived in Oregon it was hard not to smoke in the rain. I just smoked whatever pipe I wanted to at the time but smoked it upside down as not to get too much rain in the chamber. Never had a problem with stain or any other issue.