In what regard? Big game hunting? Long range accuracy?
7mm Mag will do both, we have one that we barely ever shoot though. Just don't have the distance to appreciate what the rifle can do, and it is a bit too powerful for the whitetails we have here.
6mm Dasher is an interesting option. Has produced outstanding accuracy out to 1000 yards. Less than 1.5" groups have been produced at 1000 yards. It is a caliber for the serious reloader, but it has a lot of potential.