This may be off topic a little but it's relevant to the original post…..,
At age 54, I'm a lifelong hunter of whitetails….mostly with a bow, but I rifle and muzzleloader hunt too. My knowledge of long range shooting/hunting is getting better but is marginal. I am an addict of nice rifles and optics and have managed to own a few.
Am I wrong in thinking that a projectile, just name one, traveling at the same velocity, will produce the same result regardless of caliber???
Obviously U can't shoot 200gr pills from a 6mm…..but something like a 130-140 gr Hammer Hunter can be loaded for a wide range of calibers. Does it really matter the specific caliber, if the ballistics are very similar??
As for the original issue of hunting Elk with a 6CM, the Hunter has to know that his range will shrink considerably. If he/she is disciplined enough to stay within the bullet's effective range and more importantly, their own effective range, I see no problem.
If it were me, I would not want to risk it. Choose something a bit more suitable, but make sure u practice with it and don't take a shot that u haven't practiced.
Good luck though.