Other than stainless and going with the shortest barrel to get good accuracy.
Barrel length won't affect accuracy as much as velocity, which could be related. I had a 10" 7-30 Waters barrel that would shoot lights out, but was slow as molasses in January. Went to a 13" and gained about 300 fps. With the 7-08 I would want at least 13" or more if you don't mind the size of the package.