RE: Barrel length- .257 Roberts and 7mm-08
With respects to the previous posters, I'd not pick my barrel length based on performance in a hunting rifle. I'd pick the cartridge for performance and the barrel length based on personal preference and convenience.
Short is fine in my life.....20-22" is my pick
However it's YOUR gyn.....if you want greater performance, look to the .280 or .25-06...but pick the barrel length to suit your tastes.
I have a 20" .270 that is a sweetie in the woods.....love it.