Don’t forget that 260 brass can be easily formed from other .308 family cartridges so you will never have to pay top dollar for hard to find or obsolete brass like some of these other cartridges. That was the deciding factor for me!
Pretty much the reason I stuck with it. That, plus dies competition seater and a a lot of brass!
The .260 Rem will do pretty much what the 6.5C will do. With hunting bullets it's gets a little more speed as it's got slightly more capacity. When shooting the heavy high BC bullets you'll have to seat deeper and loose some capacity, but they'll still be neck and neck for MV. I originally bought a Rem M7 in .260 for my son as a starter rifle and loaded 100 grain bullets at 2800FPS as a "youth" rifle. As he grew I stepped up my loading to the 120s. He killed 8 or 9 whitetails with it and I killed a couple more, all 1 shot from 130yds to a little over 300yds using the 120BT. I wouldn't bother shooting deer with 140+ bullets, just not needed.
It does what it's supposed to do as far as a hunting cartridge, Remington was just shortsighted when it came to the twist. A couple years ago I had the rifle "rebuilt" using a PacNor 20" 1:8 twist 3 groove barrel, Timney Elite trigger, Graphite Black CeraKote and a Manners EH8 stock as my idea for a stand/blind rifle that could stretch the distance if I had to. It's just at 7lbs all up due to the 2B barrel profile:
Accuracy is sub moa with everything I've put through it while wearing a 2.5-8x36:
With the 120s I get 2930 FPS and with the 130ABs I get 2840FPS from the 20" 3Groove barrel. As it's set up now it's easily a 400+yd deer rifle, that's pretty handy in a blind. IF I mounted a different scope I could take it further, but it'd screw up the handling, which is about perfect now.
Buuuut,
IF I was starting from scratch, didn't reload and the deal on the rifle wasn't a killer, IE too good to pass up etc. I'd walk away. The 6.5C will do the same thing and can be found on a Walmart shelf.