Sinclair Stainless Steel 30 Calibre (.307") Expander Mandrel
Sinclair expander mandrels are made .001 inch larger than the turning mandrels. The shape, finish, and size are the result of years of use and experimentation by many hand loaders.
Using an expander mandrel prior to neck turning sizes the case to fit the neck turning mandrels perfectly. This correct fit makes the turning process more precise and much easier. Any of the mandrels can be used to expand cases up to the next calibre when used with the Sinclair NT-EXP (Expander Body).