buckstix,
Before you buy bullets, be sure to "slug" the bore. Some writers have put a lot of work into finding .354-.355" rifle bullets but both of the 9x57 rifles I have owned had .358" groove barrels, plus one a good friend had was also .358". Loading data for the 9x57R is harder to find than 9x57. These two cartridges seem to be an exception to the general rule of a rimmed cartridge being loaded to less pressure than the rimless version, so you can use 9x57 data and most likely American bullets. I have heard from trusted sources of some rifles having smaller than .358" barrels (one as small as .352"), consequently the mention of slugging the bore.
It looks like a great rifle in a great caliber, enjoy.
Mike