I recall that we have visited this subject several times in the past. The musket caps will stay on if you take the time to pinch the petals a little - and particularly if you machine a little groove in the nipple where the cap pinches against it. However, I failed to do this on opening day this year and, after sitting against a tree for about two hours, happened to glance over at my Black Diamond only to discover the cap had fallen off somewhere in the dark. Good thing the elk hadn't decided to start moving through yet.

In terms of moisture resistance, however, I soaked a couple of musket caps in a glass of water for 30 minutes - pulled them out and blew them off - and they both went bang - no problem.