FL die and lee collet, it don't work

I have heard of going next size up in caliber but my question is would it size whole angle of shoulder and would angle be the same, I just bought a Redding body and do neck in separate operation but could definitely see how going up in caliber of die could not work neck so much and running mandrel through to get final neck size.
 
For me the biggest culprit contributing to runout has been using a FL die with expander, also getting rid of my Challenger press and getting a better press has also made a difference but don't expect a 70 dollar press to be a precision piece.
 
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