Sectional density (SD) of 140gr 6.5mm Nosler Partition is 0.287
Sectional density of 180gr .308 cal Nosler Partition is 0.271
Considering the velocities of each, the 6.5 Creedmoor 140gr Partition will likely match or exceed the penetration of the "theoretical" .30-06 Springfield w/180gr bullet the author mentioned in his story, a round he felt many would consider a better/more socially acceptable choice than the 6.5 CM he was using.
He has a point. The 6.5 isn't giving up anything in
penetration to the grand old .30-06 cartridge. It is giving up diameter & kinetic energy, though. From a tree stand on a bear bait, the 6.5 CM is a plausible choice (not anyone's first choice) and the author concedes that fact. But the point was, penetration & shot placement are the keys in any hunting situation and he had those covered.
The article made me think about how wrapped up in CARTRIDGE choice we get when bullet choice, sectional density, and ease of shooting accurately are the more significant factors to consider. A guy or gal shooting a 160 grain bullet out of a .338 Win Mag in a rifle that kicks like a mule & makes the shooter flinch would probably be a worse choice than a 6.5 Creedmoor shooting a deep penetrating, soft kicking 140 gr Nosler Partition bullet. The key factors being shot placement & penetration. Expansion helps enlarge the wound channel so that has a roll to play, too. 6.5 CM met those criteria without being ridiculously underpowered.
I wouldn't pick the 6.5 Creedmoor for a grizzly or brown bear hunt, but considering the author's living location (Fairbanks, Alaska) & hunting situation (hunts from tree stand, over bait) and occupation (journalist for hunting magazine) his use of the 6.5CM to show it can be done & isn't an outlandish choice, as many might assume at first glance, makes a lot of sense. Gets clicks, sells magazines, generates conversation, and makes millions of 6.5mm Creedmoor owners pleased as punch. Mission accomplished!