I am not so sure about that. Reason being during the various wars a person hit with a 30/303 cal bullet was effected measurably more than one hit with a 6.5mm bullet. yes there are some factors to take into account. The bullets were FMJ not sporting. However some FMJ's were designed to bend and cause a larger wound channel others were not. That is, I do not know if the 6.5mm bullets were designed to bend on entering a body. I have noticed the different effect on pigs that a 303 FMJ and a 6.5X55 FMJ causes. Unfortunately two people I was hunting with in my younger days, who should have known better, decided to use FMJ's. None stopped the animal straight away unless hit in the shoulder or neck. Those that were heart lung shot with the 303 did not stagger/run as far as those hit with the 6.5.

Where am I going with this? Simple, the 308 sporting ammo should be putting a bigger hole in the game than a 6.5. So with a lung only shot the larger calibre should be more effective. Hit in the shoulder, heart, neck, spine I can't see there being any detectable difference given the game is not Elk or bigger. Not saying 6.5 is not an Elk calibre.

Meant to add,

I do agree that ballisticlly the 6.5 is better than the 270 and I think the 7mm but the larger bullets put a bigger hole in the critter. If I was to be buying a 270 today would I or would I go the 6.5. Still go the 270 here simply because of the ammo situation and I can legally hunt Sambar in Victoria with a 270, I can't with a 6.5. If I was into long range shooting a 6.5 is what I would have.