I have often found rifle ammo both factory and reloaded, safely stored away, decades after I sold the rifle. As a rule I will give away factory ammo, with the rifle, if to a private buyer, but not any reloaded ammo. Sometimes you find stuff you forgot you ever had, sometimes it is stuff you expected to use in another rifle, which so far you have not gotten around to buying. And sometimes it stuff given to me by friends, getting out of shooting and figuring I might need it later. It’s like Christmas. I’m told Alzheimer’s is like Christmas every day but not so much in a good way.