First off, why do we not see a lot of mention or many people shooting the 264 win mag?
Secondly, what are the pros and cons to these 2? How do the balistics compare compared to powder consumption?
You must realize the 264WM is so large as to be completely uncomparable to a 260rem..
+26gr over a 260, which already holds plenty of capacity for the heaviest in 26cal bullets.
+17gr over a 6.5x55, the edge of practical.
+14gr over a 6.5-284, which is a barrel burner.
Well, there is no doubt a 264 could kill pretty much anything!
Does that help?
The first thing is you need to figure out your goals. Do you want a volume shooter for targets & big game, if so the 260.
Do you want a high performance long range Big Game rifle, 3500fps with 120 instead of 3050, 3200 with a 140 or 2700fps & results that follow.
It's all application driven instead of which is "better".
I just got a 264WM & the case cap./barrel life doesn't mean Doggy poop, as I have a 300WM & 25/06AI to share the burden & have volume rounds too.
So, trying to asswer this question doesn't mean much without knowing what you want to do with the rifle.
I don't think the contest is between the 260Rem and the 264 Win Mag.
There's more of a contest is between the 260 Rem, 7mm-08, and 308 Win.
Where the 260 Rem gives long range and low wind deflection while the the 7mm-08 and 308 trade that off for shorter range energy.
The situation changes with the 264 Win mag, the 7mm Rem Mag, and the 300 Win Mag
The larger case can provide enough energy to drive the heavier high BC bullets well beyond 1000 yards with more retained energy. With higher velocity the wind deflection and drop differences are less apparent between them.
Of those six cartridges the 264 WM is definitely the hardest on barrels. It's acceptable if it's used for hunting, but it makes one not want to use it for practice. That really does make a difference when selecting a rifle.