Your seat stem should have #20 stamped on it. If that checks out, call Redding and they'll send a new seat stem to you that contacts the bullet ogive higher, seating the bullet deeper. It'll be a #6 or 7. I'm at work and can't remember which they sent to me for my 30-30 seating die. You are correct to back the seating die off one full turn for no crimp.
