A few things:

First, that is a neat rifle. Looks like what Ludwig Olson calls a "Army Hunting Rifle" that had the bbl lopped to 22".

How about some help from the Mauser experts? Guys, any more details?

Also, I can guarantee you will find that rifle to be a Different Animal when loaded with European full power factory loads or comparable handloads, a totally different species than with the sort-of ".30-30-ish" Remington ammo. For example, the Lapua 200 grain factory load at just under 2,500 fps will let you know for sure when it goes off in a 6 lb rifle with a hard buttplate...

I did some terminal testing a while back on the cheap Remington 185 grain bulk bullet {designed for the 8mm Rem Mag} in the 8x57 and found it to be a deep penetrator and I suspect it would make a very good 100 yard heavy game bullet in the 8x57.

Here are some of the tests of it and some others:

http://forums.gunboards.com/showthread.php?t=1265

http://forums.gunboards.com/showthread.php?t=1254

http://forums.gunboards.com/showthread.php?t=1248