I have three things to share here:
1. I worked with a man a few years ago, who worked in the S4/quartermaster shop of his unit when he was in the Army in the 1960's. He was ordered to clear out an ammo shed. The ammo was from World War I. They "cleaned it out" by firing it, and they had no misfires.
2. On page 43 of the 8th edition of "ABC's of Reloading" by Bill Chevalier, there is a discussion on primers. It discusses the problems with mercury primers, and then talks about non-mercury primers and says, "However, ammunition loaded with chlorate priming made during the Civil War is often still viable, so long as neither the powder nor the priming compound has been exposed to moisture." This book was published in 2008.
3. Keep it dry, in a temperature controlled environment, and put the ammo in your will. Make sure to include one box to a few liberal relatives.
-SquirrelNuts