Re: 7mm STW 26" or 30"
I would go with a 1-9 twist on whatever barrel you use. I am not sure how the other fella got a 180 to stabilize in the 1-10 or 1-11 twist.
Any of the top barrel companies will work. My normal STW builds are usually 28" barrels. It seems to be a good compromise. I would probably go with a Broughton or Rock barrel. My dad has a 28" Lilja barrel STW, and I have a 28" Broughton barrel STW. My rifle is 100fps faster with the same load. My reamer was used to cut both chambers and we used ammo that I had loaded for my rifle. This has been the case with a few of them I have built on Broughtons. I run the 168 bergers at 3380fps out of my 28" barrel. I never ran the 180's in this rifle...mainly because a I had a 7mm/338 Lapua Improved that launched 180's at 3500+ fps.