RE: Why not 180 grain .270??
For every rifle there is the medium. The medium being the most nock down the most tragectory and the most accuracy you can get out of a caliber using a specify weight of bullet. While in a tight twist the 270 could and would shoot the 180gr mediocre. That bullet would be seated very deep in the case. I'm afraid in the end it wouldn't preform as well. The 270 is made to shoot 130,140, and 150gr bullets at optimun preformance. There is a reason the heavier bullet is not listed. The 30-06 is larger dia which make the bullet shorter. So they can make heavier bullets for that .308 caliber. Its simple mathematics.