Long story short, I acquired quite a bit of sealed Hercules powder: a 15lb cardboard keg of Bullseye, 12+ lbs of 2400, and some others. Everything looks great from what I opened, and obviously I'll keep an eye on things as I use them. No smells, funny appearance, etc. I know this stuff isn't necessarily equivalent to the modern Alliant powder, but I'm not sure how to go about finding a starting point to use it.
My first thought would be to just find an old Hercules load manual from that era (the 2400 is dated on the containers 83 and 88) and do the normal load workup, starting on the low end. I haven't had much luck digging something like that up online. Does anybody know of any sources for a PDF along those lines before I hit up eBay for a "vintage" manual?