I'm using a seating die that came with my RCBS FL die set. The way I set the die up is I run the shell holder all the way up as far as it'll go and I then screw my die down all the way until it's touching the shellholder. After that I back it off a quarter turn to where there's about just enough space to slide a sheet of paper between the die and the shellholder and once I have it where I think it needs to be I screw the lock ring down into place and tighten the set screw down tight. The next thing I do is back the seating stem off a little bit and seat the bullet a little bit at a time measing with calipers after each time until I get it to the correct c.o.a.l. All of my dies are fl die sets made by RCBS.