What atmosphere are you figuring that in?
The "Needmoor" is 2000 fps at sea level and 60 degree.
I have your 270 WSM 140 accubond at 1780 fps in the same conditions? So how much more does the 270 WSM need over the "Needmoor" .
Like I said I will concede that the 6.5 CM does recoil less if thats what you mean by pop gun. But if a bigger boom on your shoulder but only to be over 10% slower at distance with 45% more recoil is your gig then by all means run your "hammer".
Neither is a bad choice no doubt but lets not act like the 270 WSM with a 140 accubond at 3200 fps whipping up on the "pop gun".