Sounds like you read those vague instructions that come with most dies. Although sounds like you are adjuzsting a FL die set.?Uncrew the seating stem (or whatever it is called all the way.
Raise the ram all the way up.
Screw until you feel it stop because it is touching the bullet.
Lower the ram and give it 1/4 turn. Raise the ram, lower and measure. If it is too long, screw a little more, raise the ram again and so on until you have your OAL.
That is how 99% of seating does are adjusted. If it also crimps, there is an additional step to get the crimp you want. Dies are usually cheap enough, I like to buy two seating/crimping and use one for seating and one for crimping. I prefer two steps.
Its all fun, i had a hell of a time with my hornady press , not knowing also being very vague in the instructions that the ram was at its highest travel just before the arm is all the way down.
full lenth size die
And to add each press/die manufsctures have thier own little quirks.
Like my pro 1000, fine press but you have to go and fine tune all the adjustment with a case in each station or as mentioned theres some flex in the shell plate.