The Sinclair TiN Expander Mandrels offer increased lubricity and abrasion resistance due to the Titanium Nitride coating, compared to standard steel mandrels.
These mandrels are designed to be 0.001" under bullet diameter for the purpose of expanding the necks of brass prior to neck turning and setting neck tension.
The product is specifically for 30 Caliber firearms with a diameter of 0.307 inches and is a middle-ground option between Stainless Steel and Carbide Mandrels.