Re: Rem260 or 6.5CM
This topic comes up so much it seems we almost need a sticky for it.
In my eyes, the two cartridges are ballistically the same, so the decision has to be made on other factors...
As mentioned, matchgrade 6.5CM ammo is available from the factory, ready to go, for a pretty decent price. If somebody doesn't reload, and has no intent on doing so, the CM seems a natural choice. However, the "custom ammo" outfits are stepping up their 260 efforts and now matchgrade 260 factory ammo is becoming more available and is also priced well. So honestly, to a non-reloader, the point is moot.
For someone that IS a reloader, the 260 has the advantage that the brass is available from many different sources including Winchester, Hornady, Remington and Lapua to name a few. 260 brass can be formed from 243 or 7-08 brass, and even 308 (pretty much, depending on chamber), so getting brass for your 260 is easy. 6.5CM on the other hand has a single source - Hornady.
However... there are a few more nuances...
The 6.5CM allows 140gr bullets to be seated north of the neck shoulder junction (NSJ) when loaded to a COAL of ~2.875", which many reloaders think is a nice advantage.
The 6.5CM also has the sexy 30* shoulder angle, which some people argue is better than the 243/260/708/308 20* angle.
As far as I'm concerned, the 6.5CM is the better cartridge, but the single source of brass is a show-stopper. I am not cool with being beholden to a single company for brass. Again though, to someone that doesn't reload, none of this makes a difference. If you don't reload - maybe research the used brass market, and see which cartridge has higher resale value, which will offset ammo cost - by selling the spent brass. My gut tells me spent 6.5CM brass is worth more than spent 260.