This is not a flame on anyone but something to think over.
One thing everyone does is use "energy numbers" which if you really break it down means nothing.
Momentum numbers of a given bullet is a much better comparisons.
Now I use to chase cows for a living and not the brightest bulb in the room but the laws of physics are laws.
If you are using a bullet that leaves the muzzle with lets say 5000 foot pounds of energy then by the laws of physic you should receive 5000 foot pounds of energy(tho scaled down) on your shoulder, and no we do not get kicked by those 5000 ft. pounds.
"For every action there is an opposite and EQUAL reaction.
Energy numbers are in fact a marketing gimmick and a way to judge one caliber or cartridge to another but in the field it really means nothing.
Inuit's have been using .22 Hornets and .222's to kill everything that lives in their country.
Neither one gives the kind of energy numbers that are called minimum for Moose and Polar Bears which just proves the point shot placement over all other consideration.
Do not misjudge my statement, I am not saying we should hunt our big game with a .22 Hornet or similar class of firearm.
But here in West Wyoming people have been killing all manner of big game including Elk and Moose with .25-35's, .30-30's, .243's, .250's, and the .32 Win Spl. not including handguns of small caliber just to name a few of the under powered calibres.
More than energy placing the bullet properly is the key.
And yes the .260, and other 6.5's including the .256 Newton are still viable to extended ranges, just look at the G7 numbers to bare this out.