[talking out my arse]
But that's the point: at recoil levels that are amenable to lots of practice, the .270 outperforms the .30-06, giving the same SD and BC as .300 win mag without the pain and muzzle blast. It seems that it's not likely that game notice much of a difference being shot with either, so why not go with the 150 grain .270?
This is an argument that leads us down to the .260 Remington and 6.5x55 on the lighter side and the 180 grain .30-06 and .300 Win Mag at the heavy book-end to get the same kinds of ballistics. If you wouldn't shoot 180 grain .30-06 in lots of practice, the .270 fills the bill better. Many would argue that the 7x57 Mauser is an even better balance. When you consider 'bang for the buck' - buck being recoil - the .270 might be an ideal bullet weight in an ideal weight gun with acceptable recoil. A .30-06 with 180s in the same gun might be a bit brisk, and a 7x57 in the same gun might be a bit slow.
The 150 grain .270 might be the perfect balance of ballistics, punch and recoil in a portable rifle that could take any sized game.
[/talking out my arse]
Of course this is all the culmination of a lot of what other people wrote of their decades of experience. I intend to find out if all this bears up to their claims, as I now have one of each.
When I sold my .270 a couple decades ago I immediately regretted it. The rifle was accurate and didn't hardly kick. But I had bought a lightweight .308 to replace it and had a deal in progress. I think I didn't understand the .270 then, because I never would have switched knowing what I know now.