I currently have a 7 STW Sendero that shoots decent. With the Bergers seated to fit the magazine (3.6"), there is no room for play and about .70" of free bore. Tis the reason I want to switch to the 7mag. I am thinking of sending it off for a rebarel. Should I go with the standard 1-9" twist? Barrel Length? Contour? Muzzle brake? While it is at the smith, I am going to have him rebore the raceways and bush the action to tighten it up.