RE: 6.5x55.....
I have shot everything from rabbits to scrub bulls weighing well over 800kg with the 6.5X55 and 140-160gr pills and I cant fault it one bit, my experiences with it is the only reason that when I was looking for a light handy little rifle for general hunting that I settled on a 260rem.
All in all the 6.5X55 is a better big game round but there very close.