i bought my pyrodex i think about 6 yrs ago memory getting bad and i don't have a problem one.Altough this is not my preferred powder i think good black powder is better that is my opinion and why i still have some of the pyrodex.i have had rifles sitting loaded and fired them after being loaded for a few yrs.longest i ever let sit or my friends that i personaaly shot was 15 yrs but it was black powder.Well i guess that is almost true a friend bought a rifle from an old gentleman that told him he loaded it 30 yrs prior and never shot it after about 7 or 8 caps she fired nicely,but don't know if his story is true or not of when he loaded it but there is my experience with the powders