I have just bought myself an old Mauser M98 in the even older caliber 9x57 Mauser. Does anyone out there have any form of reloading data for this caliber?
I mainly have the powders from Norma and Vihtavuori available, but I also have a can of Reloader 10x in my possession. All data are of interest.

Best regards

I bought a 1908-vintage Oberndorf Mauser in 9x57 last year -- I assume this is similar to your rifle? I started loading with 200 gr and 250 gr Hornady roundnose bullets in .358 diameter, because they have short bearing surfaces and I wanted to avoid pressure problems if the bore were in the .356 range. I have no experience with the Euro powders -- I've been using IMR 4320 and H335. I started with H414, but found it a bit too slow to produce good results.

Can you buy 9x57 brass? I have to make mine from 8x57, which isn't all that difficult, but adds a couple of steps.

In any event, I think the commercial Mausers are great old rifles and the 9x57 is a well-balanced cartridge for big game hunting.

I was told it was an old Obendorff Mauser, but my licens says Geco as manufacturer. I still have to pick it up from the seller to check. Anyway it did only cost me about $50 so

IMR 4320 fist nicely in between Norma 202 and Vihtavuori N-140. Just about the burning rate that I had in mind. I might be able to get some here in Sweden if I'm lucky.
May I venture a guess... If I start with about 40 grains IMR-4320 it sounds not too dangerous?
Do you mind to send me you starting loads, or hunting loads for that matter. I just have to know so I can calculate my on starting point.

About brass my easiest way is to get some 9,3x57 cases and just run them throug the dies - finished.
The 9,3 is quite popular in Sweden so there are no shortage in cases, new as well as 'fired-once'. By the way, what dies do you use. I have found Redding at a reasonable price ($56 at Sinclair).

Honour,
I once developed loads for a friend in Texas for her 9X57mm Mauser, and her 9X57Rmm Drilling. I used Rem. 8X57mm cases for the rimless Mauser round, and 7X57R Norma brass for the 9X57R. Here are my two loads, which were very low-pressure, quite safe. (I used .358" bullets. These guns had .356" and .354" groove diameters, but when fired, their case mouths freely released the bullets - this is ALL that is required for safely firing slightly oversize bullets. They swage down to groove diameter before peak pressures are reached!!)

9X57mm Mauser: 180-grain Speer bullet; 51 grains IMR 4320 - MV 2550 FPS VERY MILD LOAD!!

9X57R: 180-grain Speer bullet; 51 grains IMR 4895, MV 2500.

The Speer 180 is plenty adequate for whiotetail deer up to 200 meters, but a bit on the light side for larger game!! I think today, I'd use a 225-grain Nosler Partition for this caliber.
My notes indicate that these are light loads, and could be worked up, one grain at a time, to probably 2700 FPS. Likewise, the 4320 load could be used unchanged with a 200-grain bullet, and would give around 2400 FPS. I believe you could load a 250-grain bullet up to +- 2400 FPS in the Mauser 9X57 using IMR 4320 powder. But be careful doing it, work up 0.5 grain at a time.

There's no reason a good M98 9X57mm can't equal or beat a .358 Winchester!!

I was very careful with the Drilling, because who knows what pressure a Drilling can take?

Good luck! Have fun! Developing loads for unknwon/obscure cartridges is what's fun about handloading! Of course, I guess in some places the 9X57mm is not that obscure!!