The difference between .30/06 and .308W with top loads in 180gr weight class is closer to 250fps not 100. I get 2950 out of my 06 with 180gr Interlocks. My .308 max load gets me approximately 2700 with the same bullets. Both are compressed loads. Downrange that initial 250fps pays off but no it isn't that much of a difference in ranges 400 yards and in. Just like the difference between the .300win mag and the .30-06 is pretty much moot until after 500 yards. I can kill anything just as dead and just as quickly with a .30-06 inside of 500 yards as the next guy with a .300WM and at half the cost of ammo, if you don't reload, and with much less recoil which allows for more practice without a bruised up shoulder. Range time is the most important part of hunting to me. To be able to accurately place that bullet in the part of the animal that will cleanly and efficiently dispatch it is paramount. Doing this requires a well fitted rifle and a lot of range time to know your own capabilities as well as the rifles. And stay within those capabilities while in the field.