You did not indicate what type of die you are using. As a general rule you first rasie the handle until the piston and shell holder are at the top of the stroke. You then screw the sizing die all of the way down until it touches the shell holder. You then lower the shell holder and screw the die in 1/4 to 1/2 more turn. This will full length re-size the case.
Note: You may have to adjust the de-priming rod. If you hold the shell holder on the die, the de-priming rod should just stick out a little from the shell holder cutout. If the rod extends out to long it will bottom out inside the case and not allow the die to go all of the way down.
How are you lubing the cases. That may be another issue. You need just a little along the body of the case and I will wipe the lube from the neck of the case before sizing. I also lightly lube inside the case neck.
In some cases with tight chambers and using mixed sheel holders I have noticed cases where the case was not fully resized. Big issue with the WSMs. As a general rule in this case shifting the the die makers shell holder will fix the problem.