I also use a RCBS 3 piece die set however I get a more uniform and consistent crimp by setting the RCBS bullet seater crimp by inserting a sized case into the shell holder and lowering the handle. Adjust the bullet seater die until it just touches the case mouth, back off a hair then tighten down the lock ring. Seat the bullet, set aside.... when ready I change dies and use a Dillon crimp die. I adjust the crimp die just enough to put a small shiney ring around the case mouth and then just a hair more. Just enough crimp to barely notice a slight indentation of the case mouth into the bullet. Out of thousands of rounds, I never not once had a bullet creep on me from recoil with this setting.