Bertram is a brass manufacture, most of their cases are boxer primed, the odd Euro case with the anvil built into the brass and no center flash hole are Berdan primed.
I tried a box of Bertram brass for my 6.5x58R Sauer and the brass needs to be anealed (Brittle, split neck on first loading without annealing before using) and the necks were very thin I had to size in a 257 sizer die with a .258 diameter expander ball to load .260 bullets. Brass made from 9.3x72R works perfect in my 6.5x58R die, no neck reaming neaded.
8x58R should be easier to make than 6.5 as there is a lot more squeezing down to do with the 6.5
