And as everybody knows, a .270 will do almost anything a 6.5X55 will, right?

65BR
You obviously have high regards for the 6.5X55 to be asking the question. I just completed building one on a Ruger #3 and have never seen a Griz. Sure have seen a train load of Black bear and wouldn't hesitate to shoot one with it. I was raised, and have hunted, in the Adirondacks where there are thousands of them. I also know that the Black bear isn't particularly known to have eaten a whole lot of folks.

A vast amount of game and numerous species have been successfully taken with the 6.5X55 however if I were going on a Griz. hunt it would be my choice to take along a whole lot more gun.

You were asking where to aim. That indicates to us that you may not have much experience hunting the Griz. That's a legitimate, reasonable, and logical question. An other question might be presented to experienced Griz hunters as to what caliber they would recommend for a hunt. It would be my estimation that very few would recommend the grand old or newly reformed 6.5X55 as a first choice for themselves.

Those are my thoughts and yours may be different.

Best to you and have a blessed Christmas.

Jim

BE STRONG IN THE LORD, AND IN HIS MIGHTY POWER. ~ Ephesians 6:10

Socialism is a philosophy of failure,
the creed of ignorance,
and the gospel of envy,
its inherent virtue is the equal sharing of misery.
--Winston Churchill