I own four rifles chambered in 6.5X55. I don't own a .260 as of now. However, as has already been said, they are almost mirror images as far as performance goes. I do give the edge to the 6.5X55 and on a modern action or a 98 mauser action they can be loaded to out perform the .260 by a pretty good edge. The 6.5X55 will probably handle the 160 grain bullets a little better as well. I really like the 140 grain Hornady Interlock and the 129 grain SST's in my rifles. I just bought a box of 120 grain Barnes XLC bullets to tinker with. By the way, all my rifles including my two customs are barreled with Swedish military barrels.

I am a 6.5mm freak, and I would say that the best choice in the .260 Rem/6.5x55 game is the rifle you can make the best deal on. The two rounds are so alike, and the only real difference is in the use of 156-160 grain bullets which will protrude into the powder space. Having said that, the .260 is such a screamer with lighter bullets, why worry? The heavy bullets are the realm of the 6.5x54mm and 6.5x55mm anyway. Then you can go to the 6.5x57mm, another duplicate round, and then up to the 6.5 Rem Mag (stubbie .270) the .264 Win Mag and the 6.5x68 RWS, but these are hard to find, hard to feed cartridges. Stick with the .260 or 6.5 Swede, either one!