I am switching bullets for my .270 and I know what my overal length is using a camparitor (sp). I bought a new seating die (not competition die) for the new bullets and need to set it up to match the OL. Do I just put a fire formed piece of brass and the new bullet in the press and keep adjusting until I match the OL? Am I missing anything? Don't be too hard on me I'm new at this.