Some years ago I bought a bunch of old US .45 ACP ammo headstamped
1918 at a gun show that the seller had tumble cleaned to make it shine.
It was in heavy plastic bags and I didn't look at it closely until I got it
home. All of it fired but there were a very few slight hangfires, just click
and boom, nothing like what happens sometimes with muzzle loaders.
No big deal and the only hangfires I have experienced with center fire
ammo.