I had a 401 Winchester, 7 or 8 years ago, that I shot some very old ammo in, old enough that it was corrosive. It was kind of amusing, I got a delayed click-bang, but it all went off. And, apparently, it all developed full pressure, every round operated that heavy action, and pressures don't seem to have to drop much to turn it into a single shot. The brass itself looked fine, no cracks or damage.
I have other ammo not nearly as old that developed lengthwise splits on the first firing, and unfired ammo with cracked necks. My suspicion is that the cases were improperly annealed in the manufacturing process.
Tim
