samiam03, yes I am following this, as I have the dozen or so others over the years and, in the words of Omar of Naishapur, "evermore Came out by the same Door as in I went."
It's because no one here has even asked, as far as I know, how one would go about solving the problem in an organized manner. Now I assume it has been solved many times but the results haven't "made the papers."
Were I a defendant in a big-buck lawsuit, this it the sort of thing I'd like to know and these are the sort of tests I would sponsor, at least as a first run, to find out.
How much pressure is "available" in, say, 18 grains of Red Dot? For this you'd need a plenty-strong "bomb" which would confine the powder to a space about similar in size and shape to a shell, a primer, and a piezo-transducer for high pressure. Light it off and measure what the absolute max average pressure is, and figure that's all you are working with if everything is going according to plan.
Do the same in an ultra short chamber so you can have a powder chamber and a wad whose open end is totally blocked by a big steel rod. It's the same sort of high-pressure vessel otherwise, and this tells you the max absolute pressure when a shell is assembled but the shot can't go anywhere.
I'd do this with at least a couple of powders, one like Red Dot, one like Long Shot, just to see what the differences are, if any.
I've no idea what the results would be, but they would put an upper limit on what a correctly-loaded shells could do. At least we'd have a place to start and can see whether we can put half the theories to bed before we begin.
Then I'd pull a book called "Firearms Pressure Factors" off the shelf and study the three or so chapters on EPE's, extreme pressure excursions. This is the "half loaded" rifle-shell stuff and while I thought on first reading the book pretty-much dismissed it, a second glance made me think I'd gotten it wrong. So I'd study that, as well as the tests done to reproduce it in the lab which, as I recall, has never happened. I'd go though Hatcher's Notebook too, since though I remember his accident analysis concentrated an poor heat-treatment (too brittle) of Springfield '03's there's always something in that book to pay attention to.
Last, I'd re-read the Scientific American article on detonation, the one I promised to Pat many years ago and which is on my floor to the right-rear and which may yet make it into the mail, having surfaced once again like a stone in an over-winter field.
When I get back from the Great Lakes Grand I'll do all of those things and have more to say.
Neil