Oh yes, the older the ammo gets the more unstable it gets. Even being submerged often does not harm it, so one has to be always careful.
The relic hunters here are always blowing themselves up. Ammo and weapons are still all over the place, not only from the War, but the revolution and before. Just 3 or so years or so ago we had some young lads digging a hot water feed pipe trench in Inkerman at the foot of the harbor, of course by hand. One of them hit a bomb with his shovel, and now we got 4 dead teenagers.
Watching the vids on youtube of some of the relic hunters will make your hair stand on end with the careless way they handle old ordinance. Not this old Shirt! Treat it with great care, always!