Lee Precision Decap Mandrel .3055 for 7.62x39 and 300 AAC Blackout

Lee Precision Decap Mandrel .3055" – 7.62x39 Russian

The Lee Precision Decap Mandrel is the decapping mandrel for Lee collet neck sizing dies: it is the element against which the collet fingers squeeze the case neck, and at the same time, it holds the pin that ejects the spent primer. This .3055" version is the one specified by Lee for 7.62x39 Russian, 300 AAC Blackout, and 300 HAM'R, and it should be replaced when the pin bends or the mandrel becomes worn.

In a collet die, the neck is not compressed by an external ring and then opened by an expander ball, as in full-length dies: four fingers squeeze it directly against the mandrel, so the mandrel diameter determines the final inner neck dimension. For this reason, Lee makes the mandrels .002" to .003" under the nominal bullet diameter: with 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 neck aligned with precision, reducing runout. The same .3055" diameter also exists under the code NS2627, but it is intended for the neck sizing dies of long-cased .30 calibers (.308 Winchester, 30-06, 300 Winchester Magnum).

Main features

• Lee designation: DECAP MANDREL .3055"
• Mandrel diameter: .3055"
• 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: 7.62x39 Russian, 300 AAC Blackout, 300 HAM'R

Recommended use

Replacement part for Lee neck sizing dies — Collet Neck Sizing, Micrometer Neck Sizing, and Ultimate Die Set — in 7.62x39 Russian, 300 AAC Blackout, and 300 HAM'R calibers. Lee lists it as a replacement for the 7.62x39 (code 91016), 300 AAC Blackout (code 91017), and 300 HAM’R (code 91636) Neck Sizer dies.

Package contents

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

Manufacturer code: NS3548