A .223 bolt gun wouldn't do for a 6.5 either. 6.5 has the same rim diameter as .308. You're right that you'd have to change the bolt and barrel with a .223.
"...308 being anything like I remember .30-06..." You comparing semi-auto or bolt actions? Makes a difference. Same felt recoil, as in none, out of a semi. About 2 ft-lbs. more out of like weight rifles and with like bullet weights out of a bolt action.
"...I want that 6.5..." "I want one" is reason enough. The brand of receiver really doesn't make much difference other than relative ease of buying one. And to some extent the ease of finding a barrel that'll fit a particular brand of action without a lot of fuss.
Knew a guy, years ago, who bought a BNIB Win M70 just for the action. I'd be thinking used, short action, hunting rifle just for the receiver and selling off the parts of it you don't want(selling the scope and stock, for example, will defer some of the build costs. Got the nice new walnut stock from the guy for $15, as I recall. Long time ago.). Isn't really the right time of year for that though. Deer rifles come cheaper right after deer season and it's too early for varmint rifles.
The "Wal-Mart test' is more about hunting cartridges, but still applies. Good name for it too. Mind you, a quick look at Walmart.com shows Hornady 6.5 Creedmoor ammo, dies and even a 2a Armament Barrel.
"...6.5CM is a "flavor of the month"..." Yep. Lotta stuff like that.
They were bolt guns, not semi auto, thanks for the information, much appreciated.