Years ago I bought a small brass casing that fits over the nipple to protect the cap and seal out moisture. It attaches to the trigger guard with a leather string.I cant remember where I bought it. Do they still sell these?
:v I believe that Dixie Gun Works still lists them as "cap covers", also you can make them from about any small caliber ACP cartridge. 25 or 32ACP cases work well as safeties as they block the hammer from the cap, and keep the worst of the weather of the cap. If the caps fit tightly on the nipple(press fit) no water will get by, especially if you put a light smear of vasoline over the cap/ nipple. :v
When I use percussion guns I protect/seal the nipple with rubber brake bleeder caps that you can get from any auto parts dealer. They're cheap & work very well.
