I have had great results using fresh .35 Whelen. I had only to run it through once, trim to length, then load.

For 9.3 X 62, check the width where the new shoulders will be. A potential problem with 'donor cases' is that of width. With 9.3X57, for example, their narrower shoulders aren't touched by the 9.5X57 dies resulting in an even slighter shoulder than on the Eley drawing shown above. Some say they've used 9.3X57 for years without having drawn them straight first, I will not.

The .30 - '06 brass was the old 'go to' in the U.S as it was (is) readily available and is dimensionally very close to the 9.5X57 from base through shoulder and, as the shoulder will be worked down (as with .35 Whelen) you'll get a proper fit without having to draw them straight first. I've been told and have read, however, that you'll have to work the neck width up in stages with one or two expanders and lube.

If you can get some .35 Whelen you'll get shoulders on one pass that match original DWM 531 as shown in photo posted above.

There is new brass available from Quality Cartridge (Qual Cart) in the U.S. with 9.5 X 57 headstamps. I have some, measures out right, haven't used it yet.

Projectiles are another issue altogether.