I've found that the Lee system seems to work best for me .I trim all my rifle cases with the Lee case trimmer ,it will trim them all to the same length with no adjustments needed. They are preset at the factory.Then I resize my bottle neck cases in a Lee collet size die ,since their's no expander pulled back thru the neck their's very little stretching. Sizing tends to stretch cases more than fireing them does. This collet die will not work for auto loaders.