Ran across this thread on the Campfire, seems to be worth making people aware of. The link to the CMP thread was provided by Denton Bramwell, who is someone I will accept, that knows a bit about playing with powder.
It concerns deterioration of powder and what happens when it does. Some interesting info from the US Military on the subject in it.
http://forums.thecmp.org/showthread.php?t=157820
this was the original thread from the Campfire;
http://www.24hourcampfire.com/ubbthr...ics/11507280/1