strictly my layman's opinion, to be taken w/ a grain of salt. the 6XC is roughly a "short" .243 that has about 7 g less volume than the .243 win case. the advantages it is designed to provide, longer barrel life, less case stretching, etc., make more sense in high-volume target shooting than for hunting. for a Blaser hunting rifle, I'd just assume use a .243 case for the 105 A-Maxes, and at least a 1-9" twist barrel (does Blaser offer that fast a twist in the .243? thats a consideration too).
all that being said, the 6XC seems to be a great cartridge, and I end up liking just about anything that starts with the 22-250 case. if you don't mind the more limited availability, etc., go for it.
