Which one would you use for hunting whitetail in the east and south and antelope, etc. in the west?
Thanks.

We can throw another one into this pot, or two, depending on who's counting. The American wildcat 6.5 Roberts and the European 6.5x57 are virtually identical cartridges and ballistically fit into that skinny little slot between the .260 and the 6.5x55.

My first one was a rechambered Arisaka which was the reason for the wildcat. WWII souvenirs were rechambered so available brass could be use. When it turned out that bore was grossly oversized, I used the action to build a deer rifle for my then wife. A set of dies had come with the original deal; the only available 6.5x55 brass was the very expensive Norma and the even more expensive Lapua; the 6.5-308 was a wildcat needing a custom reamer and custom dies. I had a new 6.5 Roberts barrel fitted and have never regretted it.

Finished rifle turned out to be pretty good and the wife turned out to be worthless, so I threw her out and kept the rifle. Never regretted that, neither.

Whichever one fits in a rifle you like. They can be loaded so closely in performance there is no real difference other than that the 260 fits in a short action.........DJ