21st Century Neck Sizing Die Body

We are excited to introduce the 21st Century Innovation Neck Sizing Dies. Unlike traditional bushing dies these dies utilize a special interchangeable black nitride coated stainless steel die insert that will size down to the neck-shoulder junction of the case. The die insert is placed into the cap of the die body and is designed to float and self-center while the neck of the case is being sized. This eliminates any concentricity issue and results in an almost perfect case neck. The die inserts are designed to eliminate case neck doughnuts if adjusted correctly. Once a case is sized with the neck die, you will then follow up with expanding the sized cases with a 21stCentury expander mandrel to set appropriate neck interference. This system has been in development for a few years now, and testing has shown some great results!

A simple set-up, die inserts are laser marked to give .0005” to .005” neck interference. These are available in .204 through .338 caliber sizes.

Die bodies in two lengths are designed to work with short cases up to approximately .308 case-length and long cases up to .338 Lapua Magnum length cases.

Set up of this die is simple. Start by minimally sizing the neck of a test piece of brass and work the die down while checking how much it is sizing the neck. You will work it down by tightening the die body into the press just until you can see it is sizing to the neck/shoulder junction. Once it is set the locking ring in place. If you have gone too far you will see that the shoulder will become deformed and the case is ruined, so use caution. We still recommend a bit of lube while doing this like Imperial wax, but it is not necessary due to the characteristics of the Black Nitride coating.

If you want to switch out die insert sizes simply remove the cap which holds the insert and pull/work it out. Place new die insert in cap and firmly press to lock the o-ring in place. This system will work with any 7/8”-14 reloading press including the Forster Co-Ax.