i hunted in rain with a flintlock no problems at all......one day it was an all day steady rain.......kept a cows knee on the lock.....kept changing the priming charge.....and it was fine........end of the day it went off like any other day........i keep my muzzle down so theres no water getting in the bore.....and if it does all the lube and the bullets tightness will keep it out for a while im sure.....unless i fill the bore with water......and id be up creek if it got in the pan and wet the main charge.....but i keep the lock covered with a cows knee and try to keep my arm over it.....works for me...........i never had anything over the bore.........