Mike, When I was younger that used to happen to me a lot.  The dry fire.  When I shot at the range I used powder solvent for my patch lube, and did the same when hunting.  It took my Dad to figure it out for me.  He watched me load like I usually do and said the he thought that my solvent/lube was seeping down into my powder as I sat and waited for the deer to come.  At the range, we just loaded and shot, but in the woods I loaded and waited.  Hence giving the solvent time to seep into my powder and wet it.  Now I use spit.  Could this be a similar case?  Just a thought? Good luck this year, that's a nice buck, dpgratz