Lee Undersize Mandrel .241" for .243 Win & 6mm Remington

The Lee Undersize Mandrel .241" for .243 Win & 6mm Remington is a precision reloading accessory engineered for shooters who demand tight, consistent bullet seating specifications. Used in conjunction with Lee Precision collet dies, this undersize mandrel serves reloaders who have experienced loose bullet tension with standard-sized mandrels or who work with harder brass requiring a more aggressive grip. Law enforcement and precision rifle competitors frequently rely on this component to achieve the uniformity necessary for sub-MOA accuracy at distance.

Manufactured by Lee Precision, this .241" mandrel is undersized by .002 inches relative to standard specifications, generating a tighter press fit when the collet die closes around the bullet. The undersize geometry increases bearing surface contact and reduces runout variation—critical for match-grade ammunition where bullet concentricity directly influences ballistic performance. The compact 3.25-inch length and lightweight 0.1-pound design integrate seamlessly into existing Lee Precision progressive or single-stage press setups without requiring additional tooling or equipment changes.

This mandrel is compatible with .243 Winchester, 6mm Remington, 6mm Creedmoor, and 6mm/244 Remington Magnum cartridges—making it ideal for bolt-action hunting rifles, precision target rifles, and long-range competition platforms. Reloaders should order this component only after confirming that standard mandrel tension is insufficient for their brass hardness and performance standards. Installation requires no special tools; simply replace the standard mandrel in your Lee collet die body and resume normal reloading procedures.