Berrien Moore,
Are you absolutely sure your gun is 8x57IR, not 8x57 IRS? The quickest way to check is to see if a .323" bullet will easily fit into a case fired in your rifle. If it does, you can use lead core jacketed bullets, If you are thinking about using monolithic bullets, you should also "slug" the bore. The reason for the question is I have recently seen a number of drillings for sale that were manufactured at a time that made IR chambering doubtful.
Mike