I've had similar rounds on the '06 and 68mm cases and loaded them from 9.5x57 levels to in excess of .375H&H levels in the 68m case. the have been good performers on our large game in Canada, moose, elk and grizzly being the quary.
: I do know, that in a good bolt gun based on a 98-type action, the 9.5X57 round is much better than factory ammo shows. I would expect up to 2,350fps with 270gr. and perhaps 2,200fps with 300gr. bullets with the modern, moderate buring powders out there. H4895 should be exceptional in this round. It would be a great round for North American hunting of any large game found there, and with 235gr.Speers at 2,500fps, would make a good thumpers for Deer and B.Bear.
: The 57mm case is a good one, and the 9.5 (.374) bore size has lots of bullet available.
: 8x57 brass is easily obtainable and simply necking it up in one pass is all that's necessary for making your brass.
: IMHO, of course.