Per the Lee instructions:


Screw the Lee Carbide Factory Crimp Die in, until it just
touches the shell holder and back out the adjusting screw.
With the loaded round in the die, turn the adjusting screw
in until you can feel it just touch the case mouth. Then
move the cartridge out of the die slightly and screw the
adjusting screw in 1/2 turn for a light crimp and one full
turn for a heavy crimp. You can adjust for even greater
crimp and never have to worry about buckling the case
as with conventional crimpers. The case is sized as it
enters the die and again as it is pulled out of the die. This
assures you every case will freely chamber in any standard
gun. Don’t expect the carbide sizer to touch every
case. It is a fail safe tool for the occasional bad round that
could ruin your day.