While old corrosive primers seem to last forever, non-corrosive ones do seem to eventually die. Back in the late 1990s a buddy of mine scored a mixed case of old pre-WW-II paper shells at a Virginia gun show. In that I had driven that day he gave me a nice box of 12-gauge Winchester Super-Speed #6 chilled, same as the 10- and 16-gauge boxes on the right in this picture --
I took them to Nebraska for Pheasants. First Rooster to get up old "Meat in the Pot" went click, click!! We tried six or eight of the shells in different guns and none would fire.