In Jan 2007 alinwa posted his procedure (short vrsion) for creating 6ppc brass. His first step was to neck up the 220 russian case with a "long tapered mandrel". Where does one get this mandrel?
You want to use an expander mandrel that is made to work with the particular neck turner you are buying; the expander mandrel will be sized to work properly with the mandrel on the neck turner. If you use a K&M turner, get a K&M expander mandrel; if you use a Sinclair turner, get a Sinclair expander mandrel; etc.
By the way, if you have never done this before, here are two other great descriptions about how to prep 6PPC brass from .220 Russian:
1. Dick Wright's chapter in the Precision Shooting Reloading Guide;
