I have some vintage ammo in box that's never been fired. I say some but in actuality I have quite a bit. I'm not sure of it's age. I acquired it through my father who passed away 13 years ago.
Check with Gary Reusze, owner of ColCart, Inc. in Crown Point. He was buying/selling obsolete ammo. He usually has a table or two at the Indy 1500 show.