RE: Why not 180 grain .270??
I would think that a .277 bullet in 180grains would be so long that it would take up quite a bit of powder space in the case, and you would also have a longer bearing surface on the bullet that would cause higher pressure, so you probably won't be able to get velocities similar to what the '06 can do with a 180grainer.
With a quality 150 grain bullet it is a legitimate elk rifle IMHO. My father in law has been killing elk with one for the last 25 years.
The good ole '06 can also fire 130grainers at 3000fps, but they don't have near the ballistic coefficient of the .277's.
But I would love to see what a 165 would do from a .270.