Interesting info there Daryl, but I'm glad you did all the fiddling around and not me.

In the early 90's, I was mucking around with a .257 wildcat cartridge. Started out with a .308 case and then graduated to a 6.5x55 case because of the larger base diameter. I had been given a 25 cal barrel with a home cut chamber and when I reamed it out for the .308 case, there was a small section on one side, with the old tool marks and in trying to get rid of them I tried the 6.5 case in an improved shape. Wide 40deg shoulders.
Accidentally it turned out to be the best performer and the most accurate, because I later upped it to a 25-284 and didn't gain much at all.

Kammerherren, good luck with your quest for the perfect load for your 8x54KJ. I'm sure you'll find one that works for you.