Darryl, I agree with you if you are looking at duplicating current European loads.

Regarding the use of 30'06 / 270 brass for 358 or 9.3 ammo, you will need to neck turn the cases after sizing. I ran into this problem while trying to make 358 ammo out of WW 30'06 / 270 brass. The wall thickness of the brass is greater at the body than at the neck. When sizing this thick brass to form the neck of the smaller case, the new neck becomes too thick. After seating the bullet, the ammo would not chamber in my Winchester Mod 70 custom carbine. I switched to 308 cases & it was a breeze (John Barsness from Rifle magazine says the same). For 57mm long cases, you might be best served with using Lapua or Norma brass.

I like the idea of a 9.5X57! I have found a Mannlicher Schoenauer 1910 for sale & it even has the flip up tang peep sight. I am wondering......

Then I would have to chose between my Simson 9.3X62 & the MS when I want to take one hunting - what a wonderful dilema to have!