A friend of mine is having his m17 re-barrelled to 7x57 Rimmed. My Woodleigh Bullets hand book says the cartridge should be loaded a bit lighter than the rimless version due to the cartridge being designed to operate in break open rifles. Without going too crazy I think the M17 action could handle some reasonable pressure, although it was designed for the 303 British. Apparently the bolt face will handle the rimmed cartridge without modification.
