I have a 9,3x74R Chapuis double rifle. I love it. It is my favorite rifle UNDER 40 caliber. The key phrase here is UNDER 40 CALIBER.

While I agree that the 9,3 will kill Buff... If you are buying a double FOR buff, get at least a 450/400.
I am taking my 450 No2 and my 9,3 Chapuis to Zim in June. I consider my self well armed. If the 450 "lays down" I will continue with the 9,3. It will do the job if necessary.