Nero - I am mainly a collector so I have been hoping someone else would jump in to answer your question. All of my Ross rifles are in their original chamberings. Over the years I have seen many Ross rifles made up in different standard and wildcat calibers. The .280 Ross cartridge is quite a potent number and holds a lot of powder. I mentioned the E. Crossman testing where he couldn't blow an M-10 action filling the entire .280 case with pistol powder (and greasing the case). The Ross action had the reputation as being one of the strongest out there. The one fly in the ointment, the mis-assembled bolt scenario would be no greater worry with a rifle chambered in .220 Swift vs. .303 British or .280 Ross. If somehow that happened, whatever the cartridge, the bolt would blow back into the shooter's face if the locking lugs failed to engage with the receiver. My best advice is to work with a knowledgeable gunsmith. There is the theoretical side of what you are proposing as well as the specific rifle you would be using. Both require proper evaluation.
