From most of the data I find the .270win generates higher velocities with the same weight bullet, let's say, 140gn than the 7mm-08.
Doesn't the larger neck mean more effecient relaese of gas to propel the bullet? The .260rem is slower again, but often the .308 seems to lag too.
What gives?

Set a .270 win case next to the tiny little 7mm-08 case and it should be clear.

Ain't no replacement for displacement. Works for cars too.

Buckshot, How right you are. October 5th of 1967 I took delievery of a 383 CID "hemi" Plymouth Barracuda fastback... beat the shi_ out of Dad's 318 Fury... Displacement is a must for raw power.