what size expander do I need

[chevyiron420]

The current expander I made for my Lee die is too small for my soft .315 boolits, so I have to make another. The question is what size do I need to make it? Its for my 32 long project. My alloy is 50\50 SOWW COWW air cooled, and I dont want to be sizing them down wile seating.:castmine:

[Mk42gunner]

At a guess, I would go for about .314". With brass springback you should get somewhere around 0.0015" bullet tension.

Robert