Here is an old thread from another 'site. There are differing opinions presented regarding the practice of merely fireforming 9.3X57 brass to create 9.5X57MS, some extinct (2007) links to suppliers, and the last post has some recipes that seem a bit 'hot' to me (such as 46 grains IMR4895 behind a 270). /eve/forums/a/tpc/f/4711043/m/801107616/xsl/print_topic][blank]

The person who posted them tells of 35 years experience with three M1910s and doesn't mention any mishaps, but I'm not in a hurry to push mine that hard. The same with fireforming 9.3 brass - no thanks, I'll use dies and / or brass with wide enough shoulders.

This is the post with the load data:

06 February 2007, 19:27sierra2
Reloading the 9.5x57mm is simple, since the bullets are standard .375 diameter and you can make your cases from .30-06 or 9.3x57mm. I have used both routes in loading for three different M1910s since 1972. I started by first using the .30-06 as the "universal donor", sometime later I discovered 9.3x57mm Norma brass, thanks to my Grandfather. The 9.5x57mm is such a mild cartridge that the cases merely expand the tiny amount necessary to build prime 9.5mm cases, which occurs in almost every instance of wildcatted brass anyway. There is no problem to be found using 9.3x57mm as the basic case.

There will be problems if you use a sharply tapered bullet like the Hornaday 270 grain or a flat nosed .38-55 bullet in your loadings. They will not feed reliably thru the rotary magazine. You need to stay with a more "standard" bullet design like the Speer or Norma in any weight from 235 grain to the 286 grain. The Speer has "always" been my go to bullet for the 9.5x57mm. As for loading recipes, "Cartridges of the World" is a good starting resource for data. Use standard large rifle primers, and remember these are 70 to 97 year old rifles. Oh yes, the flat nose 255 grain bullets made for the .38-55 WCF do shoot well in a 9.5x57mm, they just do not feed thru the magazine.
Recipes - Here are some old ones I have used as starters -
235 gr Speer 43.5 gr IMR 4895
270 gr Winchester 45.5 IMR 4895
286 gr Speer 43.5 gr IMR 4895
286 gr Speer 42.0 gr IMR 3031
270 gr Norma 46.0 gr IMR 4895
270 GR Norma 46.0 gr N201
All loads were fired first in .30-06 based cases and later in 9.3x57mm based cases. Another comment, I've standardized on the 235 grain Speer bullet for reduced recoil because of my arthritis.
Also, you can buy perfect NEW 9.5x57mm ammunition from KYNAMCO via
CONNECTICUT SHOTGUN MANUFACTURING CO
of 35 Woodland Street, New Britain, CT 06051-1692
Tel 1 800 515 4867, Fax 860 832 8707
Website : www.connecticutshotgun.com
Email : galazan@aol.com
I have a friend who has purchased several hundred rounds of their 9.5x57mm via the Connecticut source, and he has been well satisfied. AND the cases are properly headstamped. However, their website is a little messed up because the pictured cartridges often do not match up with the actual specifications. I think this is because someone (not a gun person) took the pics from their illustrated catalog which is very detailed, and very confusing.

LLS
Mannlicher Collector