Any of the previous 6.5's are excellent rounds. I wish I'd gotten on the 6.5 bandwagon years ago and all I can say to the guys who discovered the 260 or 6.5X55 earlier is congratulations, you were smarter than I was.
But the Creedmoor version takes the best of both and addresses shortcomings of both in order to make a BETTER cartridge. The difference may not be huge, but is enough that it will kill off the 260 in much the same way 243 killed the 244.
It is as fast as the Sweede, faster than the 260, (especially with heavier bullets), and more accurate than either. It fits in common semi-autos which is something the Sweede can't do. And you can buy off the shelf rifles designed to shoot the best bullets available today as well as buy off the shelf match grade ammo at reasonable prices. Can't do that with any other 6.5.
