I'm not at all surprised that the Preacher was busily searching for examples of those numerous fools that Clapper Zapper claimed are blowing up a bunch of shotguns by loading them with Military Surplus Rifle Powder.
I myself wouldn't be surprised to learn that someone actually tried it. Clapper Zapper is probably busy compiling a big list of examples. People try all kinds of crazy things in reloading, and many other pursuits. A high school buddy blew up his brothers shotgun by experimenting with a duplex load of shotgun powder and FFFg Black powder. I once witnessed a co-worker using a 220 cu.ft. oxygen cylinder in place of compressed air when spraying lacquer. I told him he was f---ing nuts, and was going to end up burned like Michael Jackson. But I'll ruin the Preachers weekend by noting that he still hasn't produced a bunch of examples of reduced loads of Military Surplus Powder causing detonation of a bunch of shotguns. Or any for that matter. Maybe he should also try other search engines like DuckDuckGo, Bing, Ask.com, etc. Maybe search on Baidu to see if any Chinamen are doing it. Keep looking... keep clicking... until the computer mouse dystonia won't let you click any more!
Yep
Hatcher's Notebook, 1966
https://books.google.com/books?id=yESNUKSg5aMC&pg=PA184&lpg“E.C.” blank powder burns with extreme speed…to give a sharp report when it is not heavily confined. An enthusiast once got hold of some of this powder, being familiar with “E.C.” shotgun powder…and loaded a bunch of shells. To try out his new load he got out his fine Lefever gun, and put up a target in the shooting gallery to get the pattern. There was a terrific detonation, and a big piece was blown out the side of the barrel near the breech, flew across the room and buried itself in a wood bench.
"E.C." blank powder is not Military Surplus Rifle Powder. Not even close. 1966 was 60 years ago... a long time to go back searching for all of these shotguns that have been detonated by reduced loads of Military Surplus Rifle Powder. And desperation is never a good look!