I just checked both dies I have, the full length and the neck sizer. Though the shaft is straight on both, the expander ball (or probably the threads on which it sits) was the problem on the neck sizer. I switched them putting the full length decapping pin/expander shaft on the neck sizing die and sized a case. Concentricity is now just about right on with the fired, unsized case. Very cool! Thanks again.

Told ya :D now if that's an RCBS part, you send it back to them and they will send you a new one for free.