I don't know if this is your beautiful rifle or not, so I hope you will not take offence, but why would someone choose a relatively mild perforiming cartridge like the 8X57IRS to build a double rifle around? Two other rimmed 8mm cartridges, the 8X65RS and the 8X75RS come to mind, which are both really high performance calibers. I suppose ammunition availabilty could be a factor, but that seems unlikely.