Re: 7 WSM - what twist for for 180gn Bergers?
a 9 twist should work just fine.
I have a 9 twist in both of my 7WSMs. They both shoot the 180 Bergers nicely.
My brother has a 9 twist in his straight .284, which is considerably smaller in case capacity then the 7WSM, and it shoots teh 180 Bergers just fine, at least out to 1,600 yards - which is teh farthest he has tried to shoot it and them.