Carcanos were made in 6.5mm and 7.35mm, but the cartridges are basically identical other than bullet diameter. They both use the same clips. You should be able to easily determine the bore by measurement or test fitting a 6.5mm or .30 caliber cartridge in the muzzle. You can buy new manufacture 6.5 Carcano from Prvi Partisan, but the 7.35 is only available (AFAIK) as fairly expensive surplus.