My Uncle has a nice old German (Sauer) sporting rifle chambered in 9X57 Mauser. He's had it for years and years and he's never shot it. I'm hoping to change that. I've aquired an old box of German made, 247 grain .355 round nose bullets. I've got a set of RCBS dies on the way, as well as 100 pieces of new 8X57 brass.
So.....
Is reforming the brass as simple as running it up into the 9X57 FL die?
Any suggestions for a mild starting load?
No need for anything more than that, I don't think this will be any more than an exercise in paper punching.

You should be safe using 9.3x57 starting loads for like weight bullets. You can probably use .358 cal bullets with starting loads as well without damaging anything. Not unlike a tight bore (.3065") Palma rifle using .308 bullets. Lead bullets open up another arena. I would suggest playing with H4895. It works great in my 9.3x57 and takes to reduced loads very well. IMR 3031 should work well too. All my data is at home but you should be able google up some 9.3 data.

Lube your necks inside very well and run them through the die, should size up no problemo.

I haven't loaded 9x57 Mauser, but have loaded 9x56 Mannlicher-Schoenauer.

I concur that sizing up the brass isn't any issues.

I ended settling on 45 gr of IMR3031 behind either 225 gr or 250gr bullet for my 9x56 M-S rifle. Fortunately it has a 0.358" bore and so I am able to use standard bullets. I got almost 2200 fps with the 225gr Sierra's, and 2170 fps with the 250 gr Hornady bullets. I'd expect something similar from the 9x57 Mauser.

Chris

Chris, what do you use for brass for the 9X56 MS? Can 9.3X57 brass be necked down to 9X57? Is that an easier or better way to go? RB

For my 9x56 M-S loads, I necked up 8x57 brass. I also came across some reformed 30-06 that I've been using. With the 9x56 M-S, the base diameter can become an issue, but fortunately most (but not all) 8x57 brass is undersized enough it's usable. But for 9x57 Mauser I wouldn't expect that to be an issue.

Any 9.3x57 brass I have gets necked up to 9.5x57 M-S!

Either necking up or down should work fine from what I can tell - it's not a big change in dimensions either way.

Chris

Here you go.

http://www.midwayusa.com/9x57mm-mauser-9mm-mauser/br?cid=20677

Var-Get and RL-15,Benchmark these are powders you should try.

Use .358 Winchester 250 gr bullet data. Do you own a chronograph?

No, maybe it's time to think about getting one.

Yup.

Hey Remember - Seen Ethan & Ira lately?

Ha! You are the first person that has ever figured out the connection, or at least the first that's mentioned it.

I've read the books. Remember Baker was the third most famous Green Mt. Boy. I think he was the one that wanted to hang Benedict Arnold @ Ticonderoga when Arnold announced that He was taking over the assault on the Fort. Ethan talked him out of the hanging and invited Arnold to join in.

In my old German guild M98 sportier, I get a good factory duplication load as follows:

Prvi 8x57 brass run through Redding FL die, trimmed to 55.9MM
NOTE: I thought that 57 mm in the 9x57mm name meant that the cases could be that long. Wrong. 56MM is MAX. according to CIP Also, Prvi brass is lighter than Winchester, or other brands, so may allow me heavier powder chg. with less pressure.

Hornady .358 250 grain RN run through Lee .357 push through size die. 3" LOA. RP - 9-1/2 primer Varget 46 grains = Velocity 2150 fps

This is the same velocity and matches point of impact to the fixed iron sights as vintage Kynoch British ammo that I have shot from the same rifle, with .356" 246 grain bullets and @ 2130 fps.

I tested this combo with Varget up to 49 grains and around 2300 fps with no over pressure signs, but settled on the factory duplication load.

I remember a Baker that lived up in Arlington. Sold me my hunting Lic. years ago. --- Web

I finally got around to necking up the new 8X57 brass the other day. It couldn't have been easier, lubed the cases with a bit in the neck and ran them through the FL 9X57 die. I'm hoping to pick up some IMR 3031 powder this weekend.