Originally Posted by Ridge Runner

belted cases headspace on the belt, ok? no matter how bad you screw up sizing the belted cases they will go off, the trick with belted cases for long case life is to set the dies where the case also headspaces on the shoulder, this keeps from over working the brass causing it to become brittle, and messing up neck tension prematurely.
You can do this with either a neck sizer or a FL sizer set to just partialy full length resize, but if you use a neck sizer there will still come a time when ya hafta bump the shoulders back as the brass becomes harder from repeated firings and grows.
RR