As for storage and usability, black powder will be useful indefinitely as long as it's protected from moisture. Contrary to at least one "old wives tale" it doesn't degrade over time if kept dry. As for loading from a flask or a powder horn I offer this bit of information: Until sometime during WWII, the standard bursting charge for a U.S. Fragmentation Hand Grenade was 500 grains of black powder - 2Fg, I believe. One pound of powder contains 7010 grains, or slightly more than the amount needed for 14 of those old pineapple frags. My old buffalo horn carries a full pound of 2F but most flasks will only hold half that or less. I decided early on that I didn't really want to take even a remote chance of having the equivalent of 14 grenades go off in my hand or next to my face, so I always use a measure. Always. Maybe if I were about to be struck by an attacking hostile with a war hatchet I'd take that chance? I dunno. (I try to avoid that situation too.) In any case, I suggest you think about that information, check it out if you like, and then make up your own mind. One request though --- If you decide to load from you horn or flask anyway, please don't do it near me?
Very unsafe practice. Swabbing after every shot is good thing and that should eliminate any burning embers, therefore, no need to blow down the barrel.
