I don't own a 9.3 or a 375 Flanged, but I'd vote on the 9.3X74R.
NE540#2 earlier this year used his scoped Chapuis in 9.3X74R to kill a coyote at a lazared and witnessed 271 yards. With both barrels! Not everyone is a good a marksman as NE450#2, but it does demonstrate how versatile these mid caliber doubles can be!