One thing I learned shooting old time black powder guns over the years is that unlike smokeless powder, black powder has a very long shelf life.
Hope to build a traditions soon.
Trying to find a civil war history ping list do you know who might have one?
Reading a period (~1875) sea story novel, there's a passage describing the powder crew on a US frigate. Nailess felt shoes, garb with no buttons, etc., and they'd march in to the copper lined magazine turn the powder kegs every so often to help keep the powder from separating.
But, this unfortunate occurrence makes the passage a description of busy work, or an exercise in safety handling the stuff in such. (Probably beat the grunt work on a wooden ship of the era)