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So far I have simply run 8X57 brass into my 9.5 dies and they chamber just fine.

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Of course they will. They aren't oversized.

Ask yourself this; do they 'Chamber" just fine because the shoulders are too low and too narrow, leaving a 'jump' to be filled by stretching, thinning, and weakening the case near the base as they are fired?



Perhaps those cases should first be lubricated and 'drawn straight' or at least to dimensions meeting or slightly exceeding proper 9.5X57 cases before sizing.

If you still have 'raw' 8X57 'donor cases' of the type that you have been using that you haven't resized yet, measure the diameter at the shoulder and length from base to shoulder. Also consider the taper from base to shoulder.

Now consider whether or not your 9.5X57 resizing die touches the 8x57 shoulder at all.

Then measure an unfired cartridge that has been loaded as you have described. Does it conform to the Eley drawing below? If not, are the differences tolerable to you?

Color me cautious, but in the past I have ordered another reloader's "9.5X57" cartridges that were made of 9.3X57 brass that had been merely run through 9.5X57 dies and had left the 9.3X57 shoulder absolutely untouched, as 9.3X57 has a lower, narrower shoulder than 9.5X57. They were sent back.

A likely result of firing them would have been that when the rapidly expanding gases hit that unsupported shoulder the brass would have stretched forward thinning the case at the 'web' area near the base. Afterward, the newly 'fireformed' case would have looked and measured like a 9.5X57 (.375 Nitro Express Rimless), but would quite possibly have stretched at the base, weakening the case which could lead to case separation after repeated use.

When resizing (and trimming excess length) of .30-'06 or .35 Whelen brass, the shoulder is driven downward from its original position, as the donor case shoulder was 'taller', leaving a true and proper new shoulder length, though still a bit narrow.

The way to mitigate these potential problems is to draw 'donor brass' to the width of 9.5x57 throughout, then run through sizing die.

I have used .35 Whelen as 'donor' brass before without having drawn them straight and have thought everything is O.K., but now view those cases with a bit of the 'hairy eyeball'.

For peace of mind, I'd recommend using properly sized new brass or drawing 'donor' cases to proper width before sizing.

Perhaps I'm just a 'nervous Nelly', but I am rather fond of my Mannlicher Schoenuer, and of my right eye, side of face, and skull. Case separations can affect such things.

Reloading is a science. Reloading for 'obsolete calibers' is an art form. Be careful and enjoy.



Here is a source for properly loaded 9.5X57 ammunition, made from Norma brass drawn straight and properly resized: Reeds

Citizen of the Cherokee Nation

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