If the 260 makes an adequate wound channel to kill the game you are hunting (which I would argue that it does for any NA game), then your only consideration is to keep the impact velocity high enough to expand the bullet properly. Those velocities are listed pretty well in the above posts.
You could shoot anything in NA with it and not tell much difference from most any other common caliber outside the really big boomers. So, "yes," I would shoot an elk with it at 400 yards.
