Quote: I know that the 11.2*72 was/is the same as the .416 Rigby, but why is it not more used today?
There is a marked difference between the two. 11.2 on left / .416 on right
The 11.2 is a very powerful round but I think its demise had more to do with the bullets offered in it's day. The .416 has a better sectional density and was offered by more makers than the 11.2. That said, with a good bullet the 11.2 is capable of taking any game animal on earth. As for the rebated rim, you can see it certainly is, but not any more than a .425 Westley.
-------------------- He who lives in the past is doomed to enjoy it.