flintlocks in the rain

[Mr. 16 gauge]

For you fellows that have been shooting for a while, what tricks, tips, and secrets do you have for a flintlock greenhorn as far as getting them to go off in the rain? I want to eventually take my .62 cal. Trade musket waterfowling, and since 'fowl weather' usuallly translates into 'foul weather', I am looking for some advantages. Also, I don't know if any of you have been duck hunting, but EVERYTHING eventually gets wet......

So, in additon to keeping my powder dry, what esle should I consider? I have heard of a product called "raincoat' that you mix with your priming mixture....good idea or bad?

Thanks in advance.