Well, I finally got around to trying out these shells at today's match. HUMONGOUS FAIL! On the first stage, the first two fired fine, knocked over the targets. Seemed comparable power-wise to my BP loads of 60gr FFg and 1 1/8 oz shot. But then when I tried to eject the empties, well, they didn't. Both hulls split and the head of one flexed enough to allow it to slip inder the extractor and require prying out. Head only came out, so I stuck my finger in the chamber to slide out the body of the hull. I went ahead and loaded two more and they did the same thing (I knew my match time was already hosed so was going for the clean match). It was an 87 second stage. I had fortunately brought another box of my own loads to finish the match. But then the second stage was 82 seconds due to the 32-20 rifle going down but that is for another topic.
I'm thinking these shells are at least a dozen years old. Don't know if it was a chemical reaction of the powder with the paper hulls (I would assume that) or what. I've still got 4 or 5, 12-round boxes of these loads. I guess I could probably reclaim the shot. Not sure if it would be worth the effort to empty them out to reclaim the primers. Heck, if I wanted to go to that kind of effort, I have scads of 20 Gauge hunting shells loaded by a brother who passed.
Also, these were the "low brass" shells. The "high brass" shells would be likely to do the same thing, but I don't know for sure. Next time I shoot BP, I should take some of those to try out after the match to be sure.