My buddy has a few sets of dies. I think Pacific?? with a cutout in the seater.

Do you drop the bullet through the hole or is it just to see it seat.

On RCBS competition die you drop the bullet in the window.

https://youtu.be/Xc1lDG9E_UI

With the old Vickerman-style dies (Herter's copied them, don't know about Pacific) you used them as you would a "normal" seating die and placed the bullet on top of the case as it enters the die. The inner sleeve would ride up with the bullet/case until the bullet contacted the seating stem.

on the ponsess warren set you drop it in the window.