Do you use dummy rounds to help get the correct coal? Once I have the desired coal I will make a dummy round to that coal. The next time I am making that cartridge I will:

1. Confirm the dummy is still the correct coal,

2. Raise the seating plug so it will not accidentally come into contact with the bullet,

3. Run the dummy round into the die and then lower the bullet seating plug until it is just touching the bullet. Then tighten the seating plug locking nut.

This should get you pretty close to your desired coal.

I leave the dummy rounds with the dies so they can be easily found when needed.