Lee Precision Decap Mandrel .3085 for 303 British

Lee Precision Decap Mandrel .3085" – 303 British

The Lee Precision Decap Mandrel is the decapping spindle for Lee collet neck sizing dies: it is the component against which the collet fingers squeeze the case neck and, at the same time, holds the pin that ejects the spent primer. This .3085" version is the one specified by Lee for 303 British, and it should be replaced if the pin bends or the mandrel becomes worn.

In a collet die, the neck is not compressed by an outer ring and then opened up 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 the 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 .3085"
• Mandrel diameter: .3085"
• Lee design undersize: .002" to .003" under nominal bullet diameter
• Dual function: internal collet sizing reference and decapping
• Quantity specified by Lee: 1 piece per die
• Calibers indicated by Lee: 303 British

Recommended use

Replacement part for Lee collet neck sizing dies — Collet Neck Sizing, Micrometer Neck Sizing, and Ultimate Die Set — in 303 British caliber. Lee indicates it as a replacement for the 303 British Micrometer Neck Sizing Die Set (code 90717), the 303 British Neck Sizer (code 91021), and the 303 British Ultimate Die Set (code 91875).

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: NS2628