Sinclair Carbide Neck Expander Mandrels are made from solid carbide for precision and lubricity, reducing galling and material transfer.
The mandrels are designed .001" smaller than bullet diameter for optimal neck tension and concentricity when used before neck turning or bullet seating.
Compatible with the Sinclair Expander Die and Neck Turning Tools, these mandrels are specifically made for 30 Caliber with a diameter of 0.307 inches.