As it is the old .318 WR in a new dress, and if his game choices include buffalo, he is probably pretty spot on. As the 250 gr .330 was considered a great cape buffalo round by a lot of the author old timers, it is probably a good minimum choice for water buffalo. Yes other rounds will do the job too.

And with the 160 to 200 gr bullet range, not too overgunned for medium game.

I would be tempted by a 8.5x63 barrel for my Mauser M03 if I didn't already have a 8x68S.