I have been out hunting 6 day in a row with the same triple 7 powder in the gun, on the 7th day I took a nice 9 point buck, so I guess as long as the powder does not get wet, who know how long it will last. I had on buddy that did not shoot his muzzleloader at all one season, and left his gun loaded with a red sticker on the muzzle so he knew it was still loaded, and the next year he went to the range and the gun went off without a problem.