Here' s the key...properly stored!!! Mostly that means not going thru climate extremes of freezing/ thawing many times, loaded ammo (including shotshells) are good for a minimum of 40 years.

If I had a box of .30-06 shells sitting in the cupboard from the 1950s, I' d take it to the range, sight in, and go deer hunting with no reservations at all.