You missed the point I was making, but that is OK.:)
If my loads were too hot for the brass, my brass would not last me for 37 years. I'm still using the same brass in my 9.3x62 that I made up for it in 1982, along for 40 years in the .375/06IMP I made in 1979.

When I picked up my second .375/06IMP bl. I converted some of my 9.3x62 brass to that chambering simply by necking it up, loading it and fireforming it to the 40 degree shoulder.

If my loads were as hot as you think, my brass would not last for 20 to 30 shots. Both of these cases display minimum taper.

If the 9.3x62's shoulder "angle" was steeper, it would qualify as an Ackley Improved shape. The case already has a .454" shoulder diameter, not .451" as I have seen printed.

Both of mine have factory commercial chambers along with a Styer rifle in that caliber from which I have a couple fired Sako Factory loads, having .454" shoulders as well.

Just mull that over. My current RP and WW .22 Hornet brass has been loaded almost 12 times and 8 for the .17AH which was necked to .17 and fireformed to .17AH after 14 loadings as a .22 Hornet - & that is all since about the year 2002.

So perhaps THIS tool has an idea what he's doing & somewhat how case shape improves or hinders extraction.