I personally have never killed an elk with any 6.5MM. But I have killed about 15 deer and antelope with 2 6.5 Swede rifles and one 6.5X54 Mannlicher.
I have also seen a bunch of deer and antelope killed with 260s Swedes, 6.5 Grendels and a few now with 6.5 Creedmoors.
Of all the elk I have seen killed with 6.5s, (those I can remember here and now as I type this)
6 killed with 6.5X55s.
1 with a 264 Win Mag.
5 with 260 Remingtons
3 killed with 6.5 CM
Various bullet have been used. Ranging from very poor to OK, to excellent.
If I were to pick just one as a deer and elk bullet to "marry a rifle to for all hunting" it would be the 140 grain Nosler Partition. Information strongly suggests to me that the AccuBonds may be just as good, but I have not had enough experience with 6.5MM AccuBonds to swear to that yet
Good post, S. I have not, nor probably will not hunt elk with my Creeds, or .260s. That being said, I have seen bullet performance on LOTS of deer and I would not feel handicapped at all with a 6.5. I, also, believe that the Partition is at the top of the list, but Hornady Interlocks, Speer Gold Dots and of course the coppers can be added to the list.