I believe one of Corbetts favourite rifle was in .275 Rigby; received as a gift for killing the Champawat man eater in 1907, from the Governor (of U.P), Sir John Hewett (I am of the understanding that this is the same as the 7x57 - not sure if they are interchangeable?)I believe Bell (in Africa) used the 7x57 a great deal. So you have a calibre used by two very famous and highly respected hunters. The Rigby name also has the nostalgia factor. Perhaps this is one to consider.
Just realised there is the thread about Jim Corbetts rifle in this section. I was looking through a reproduction of an old Rigby catalogue, dated 1924, that I have. Their model 4 rifle is in 350 Rigby magnum and below the details of the calibre is a picture of a Tiger; I guess to indicate its suitablility for that animal. Don't know how difficult 350 Rigby brass is to find?