I am in the process of having a 7mm STW built and need to order the barrel. It will wear a suppressor and i am not sure what barrel length to go with. the suppressor is 9 inches long. Can i have a heavy contour 20" tube and get all the benefits of the round. I am hoping i can keep the finished length with the suppressor under 30". Anyone have any insight on this or know someone running an stw suppresed. thanks.