The ballistics of the 260, 6.5x55 and 6.5x47 are all very similar. I am making a bit of an assumption here but if the brass of the 6.5x47 is going to act the same as that in a 6ppc then the brass could be used up to 30 times each. That would make the brass actually cheaper to use than that of other calibres when paying less than £50/100.
Was also interested in the 6.5x47 but looking in to the availability of ammo it would have to be home loading unless I am wrong the only off the shelf I could find was Lapua scenar which is a hollow point target round. But still like the idea, in the end I have settled on 6.5x55.