[gary0529]

In a word, just about forever.
I have 30-06 ammunition I reloaded as a kid in the late 50's and I will pull 2 or 3 out every year just to test.
Every one still fires just fine.
Like JLA noted unless you really try to destroy the stuff intentionally it will usually work just fine.

As to "got you covered"--not hardly. I consider 20# of most used powders and 10000 primers my baseline.

Just sayin'

Gary