Hmmm...I have some WWII original ball 45 ACP that still shoots very nicely. Only problem is that you have to clean the weapon quickly thereafter because it is corrosive.... from a 600 rd tin I bought 15 years ago.
See? :o)
I've had a bad experience with "old ammunition" I took my mother, sister and a couple of my father's hand guns out to the range a couple years ago. Amongst the firearms was a .25 (mother) and .32 (sister) and a .22 (all semi auto). A couple of these are problematic firearms with good ammo. The Taurus .25 auto jambed a ball in the barrel and split the gun on the next shot. The .32 wouldn't fire more than 3 rounds before jambing (Beretta I think). I had two rounds damn near fall out of the barrel after fizzles. The .22 auto has been a problem since I first shot it as a kid (may or may not have been the ammo).
We quit early so I could go have some discussion about the chlorine filled bathtub my father must have been storing ammo in. He said, "Oh, BS! Ammo doesn't go bad!" I showed him what was left of my mother's Taurus and the impacted lead still in the barrel.
BTW - Taurus replaced the gun no questions asked. You do have to give them credit for service. They do make some nice pieces now a days too.
I steer clear of "old ammo" bought or stored by others. I keep my ammo in actual ammo boxes with all seals in tact.