Lee Precision Decap Mandrel .255 for 25-06 and 257 Roberts

Lee Precision Decap Mandrel .255" – 25-06 Remington

The Lee Precision Decap Mandrel is the decapping mandrel for Lee collet neck sizing dies: it is the element against which the collet fingers compress the case neck and, at the same time, it holds the pin that ejects the spent primer. This .255" version is the one specified by Lee for 25-06 Remington and 257 Roberts, and it should be replaced when the pin bends or the mandrel becomes worn.

In the collet die, the neck is not compressed by an outer ring and then opened by an expander, as in full-length dies: four fingers squeeze it directly against the mandrel, so it is the diameter of the mandrel that determines the final internal measurement of the neck. For this reason, Lee makes mandrels .002" to .003" under the nominal bullet diameter: with a brass spring-back of .001"–.002", the finished neck remains approximately .001" under bullet diameter, which is the correct tension to hold it. Lee describes this system as capable of producing a precisely aligned neck, reducing runout.

Main features

• Lee designation: DECAP MANDREL .255"
• Mandrel diameter: .255"
• Lee design undersize: .002" to .003" under nominal bullet diameter
• Dual function: internal reference for neck sizing and decapping
• Quantity specified by Lee: 1 piece per die
• Calibers indicated by Lee: 25-06 Remington, 257 Roberts

Recommended use

Replacement part for Lee Collet Neck Sizing, Micrometer Neck Sizing, and Ultimate Die sets in 25-06 Remington and 257 Roberts calibers. Lee specifies it as a replacement for the 25/06 Neck Sizer die (code 90957) and the 257 Roberts Neck Sizer die (code 91007).

Package contents

The replacement part is supplied individually and includes only the decapping mandrel. The die body, collet assembly, and other die components are not included.

Manufacturer code: NS2623