Of the calibres and rifles I have my first choice would be 375H&H in a Rem 700 with 300grain round nose pills, This is lighter and quicker handling then my CZ550's followed by my 35Sambar in a Ruger Mk11 using a 250 or 275grain Woodleigh.

If buying a rifle specifically for this then a light 416 Rigby or 404J with a 22 to 23 inch barrel.

Would never be able to afford a good double but a Bakial in 45-70 for close range.