6.5 versus 7mm

[WildRose]

BC, MV, ES, Ft-lbs, blah, blah blah...

To your point, even more important is being comfortable with and confident in your equipment.

That deserves a repeat.

Comfort level and confidence levels along with simply knowing your rifle/caliber's capabilities are incredibly important.

If you flat know you can put it in the bread box everytime you pull the trigger, the subtle differences in ballistics are really irrelevant.