Not too much difference between the 6.5 CM and 7mm-08. IMO…two short action peas in a pod, really. Using 140 gr bullets, loads of 41 gr powder gives 2800’/sec. +/-. The 140gr., 6.5 bullet is a little more slippery so effective range might be a bit further.
The 7mm-08 can efficiently use heavier lead bullets up to about 160gr. Much heavier/longer and the bullet starts cutting into powder space. Using heavier available bullets, you could make the assumption that the 7mm-08 might be slightly better for larger game (moose/elk) than the 6.5CM.
The 7mm-08 is my primary hunting cartridge. Found a sweet little Cooper Jackson Hunter at prophet river about 10 years ago. It’s a joy to carry and shoots really well. Weighs in at 7 lbs with scope and shoots sub 3/4 MOA (3 shot groups). I use the 140gr. Nos. BT’s for deer…kills really well to 400+ yds (last one was 450yds…longest kill shot of my life). For bigger game, I switch to 140gr. nos AB’s and usually try to reign the distance in to under 300yds if I can, just to be cautious.
Aside from everything else, the 7mm-08 and 6.5CM have this in common…the low recoil makes them fun to practice with. More practice makes a better marksman.