Patrick, the '93's had a two-lug bolt where the 98's had a much stronger three-lug bolt. Additionally, some of the steel used in the 93's was not the best. While the new .458 barrel would be capable of withstanding the pressures of the big round, I'm very doubtful that the rest of the gun would be able to. If that bolt fails, it's going to fly backward directly into your face.
That would not be a fun experience.