21st Century 7mm, Black Nitride Caliber Specific Expander Mandrel

Our Caliber Specific Expander Mandrels are now available in Black Nitride!  Black Nitride adds a degree of hardness and friction reduction to the surface of the mandrel.  This helps minimize galling that can occur.   

Our Black Nitride Caliber Specific Expander Mandrels are available in .0005” increments in calibers 22 to 338 and are available in seven sizes per caliber from -.003" below to caliber diameter.  Incremental mandrels will allow the reloader to find proper neck tension to fine-tune their loads. We recommend our Moly Dry Neck Lube for use with all of our expander mandrels Moly Dry Neck Lube (21stcenturyinnovation.com).

Kits include all seven sizes per caliber.  Kit pricing has a savings of 10% built into the kit price.

Expander Die Bodies sold separately.  

21st Century Expander Mandrels and Arbors are designed for proper fit in our die bodies. While these may work in most Sinclair and PMA die bodies we cannot guarantee proper fitment in those bodies.

Machined to hold a tolerance of  +/_  .0002" 

*PLEASE USE MICROMETERS TO MEASURE