Since your shooting pellets with a #11 cap, when you change over to 209 primers there will be a difference. Simply because of the degree of ignition fire. #11 caps are not considered strong enough for pellets although I know from personal experience it will set them off. I am guessing your problems.. when the weather gets nasty up there, is because of the #11 caps and shooting pellets.
Personally I would change to loose Pyrodex RS and stick with the caps. You'd have just as good ignition, cheaper shooting, less fouling, and the accuracy should be the same if not better.