A 416Taylor with a 1-4 Schmidt&Bender scope and 410grn bullets at 2280fps would be my pick for a Buffalo bolt action rifle set up.
IMO, The 9.3x62 is a sensible minimum for Buffalo.
Good Buffalo bullets are Swift A Frame softs and Woodleigh solids.
I would like to try North Fork and Barns X triple shock bullets.
And as JPK has said, Using an open sighted Double rifle in 400, 450 or 470 is great fun but do expect to mis some opportunity's.

This Buff coped two 470 rounds as it spun around to take off.

My next rifle should be great for Buffalo, a SEARCY 450/400 with a QD S&B scope.