Alls Ill say about it is I have both .243 and 6.5 cm and I shoot the 6.5 with 130gr bullets at near .270 velocities, and we all know the lethality of the good ol .270.
Same velocities from my .243 but with a 105gr bullet.
Make sure your barrel twist supports the heavy for caliber bullet selection if you go that way. Also dont just look at muzzle velocity stability, look at down range velocities to determine where/when the bullets enter marginal or worse stability.