As for popularity, I recently looked at the MidwayUSA website, and Midway is perhaps the biggest retailer of shooting stuff of any of the present Internet companies. They list 27 kinds of .260 ammo and 51 kinds of 6.5 Creedmoor.

Wow, now that's relieving John. You just scored a point in this discussion.
And you are 100% correct in the specs being "all over the page" from various countries and makers chambering the Swede, but I do not think it could not be done. CIP and SAMMI both have specs for the chamber. If I were in charge I'd pick the SAMMI and go with that from that day forward. True you can't change the past, but you don't have to keep making the same mistake either.

I can see the point of just buying a CM and avoiding the problem or even the potential problem so again that may be a point on you side. But the idea that the 260 rifles could not be set up for the longer mag and throat is just someone in the industry not paying attention.......or just not giving a c..rap I made a 260 for a friend in Reno on a KAR Mauser with it's longer magazine (then the Remington 700 I mean) and the rifle is a super good shooter and he uses the longest VLD bullets he can buy. No problem. Makes me wonder why the industry can't see that it is a simple problem to fix.

But overall the CM is a very fine shell. One of the better ones, and one of only a few "new shells" I'd agree has a reason to exist. It really is good. I think it's good because it attains the same goals successfully that the 6.5X55 did, ( or close enough to not worry about the difference) and that is wonderful.