Sinclair Carbide Neck Expander Mandrels are made from solid carbide for closer tolerances and increased lubricity, reducing galling and material scratch risks.
These mandrels are designed to be .001" smaller than bullet diameter for optimal sizing before neck turning or bullet seating, enhancing concentric necks and neck tension.
The mandrels are compatible with the Sinclair Expander Die and all Sinclair Neck Turning Tools, tailored for .284 Caliber, 7mm with a diameter of 0.283 inches.