I saw you mention this in another post awhile back, with 30-30 ammo, IIRC, and have been wondering about it. Because it's extremely anomalous, especially if it happened with a bunch of stuff, or more than a few different boxes. And I fully believe your account - I'm just really scratching my head about why it happened.
DOD did studies on ammo storage, multiple times over decades, and found that as long as small-arms ammo is stored in a cool, dry place, it lasts, quote, "indefinitely". When I was a kid, friends of mine and I actively hunted down the oldest ammo we could find, between gun shows, garage sales, and our dads' stashes. We shot stuff that was pre-WWI, and it went bang, reliably. Every once in a very, very long while there would be a dead primer, but I want to say it was less than 3 times, between all of us. But we never had any split cases. The only time we did have problems with any ammo, was paper-hulled shotgun shells. It was common for them to be hit or miss in going bang, reliably. The only asterisk is that we lived in the high desert, so it's dry here. But, that doesn't mean the ammo was always here, and this part of the country swings from sub-zero to 100F over the year, commonly.
The only time I've personally seen ammo "go bad", is when it's been left in the sun in a window, like on a work bench or the like, out in a shop. Meaning, extreme heat and cold swings over the course of a year or so, plus sunlight.
The only time I can recall anything similar to what you're sharing, is a DOD study on what happens to ammo when it gets heated. Can't recall if they did multiple cycles, but they did heat ammo up, and, again, IIRC, to decrease its humidity. And at some point, guns started blowing up. The ammo ignited fine, but with less humidity and/or changes in the propellant, the cartridges just started detonating actions.
So what you're experiencing is a big, anomalous mystery to me, and I'm extremely curious about it. The only things that come to mind are possibly that the ammo got heated, the ammo was severely desiccated from desiccants, or something was wrong with it from the factory. Even the desiccant thing is pure conjecture and speculation, as I'd suspect it would take cycling desiccants out over years to decrease humidity that much in powder for it to detonate. Can't think of any other variables or possibilities, based on what you've described though. But I would very much like to figure out what might have happened.
Was this just one box of 30-30, or did it happen with a bunch of other stuff?
