Assuming this is a 98 action, the new bolt would need to be checked with headspace gauges at least, so this is probably something you want a gunsmith to check for you. Physically the dimensions for 30-06 and 8mm Mauser on the base of the cartridge case are the same, according to a Speer reloading manual I have, so theoretically you should be able to get an 8mm bolt and use it. Once again I stress you should have it checked by a gunsmith before shooting.