The RCBS Neck Die Set is a specialized reloading two-die set designed for bottleneck cases to be fired in bolt-action rifles only and is recommended for cases fired out of a specific rifle and neck-sized to go back into the same rifle. The Neck Sizer Die Set consists of a Neck Sizer Die with an Expander-Decapping Unit and a Seater Die with a Bullet Seater Plug. The Neck Sizer Die resizes the neck only, without touching the shoulder or body of the brass casing. This ensures a precise and consistent amount of neck tension, which can improve accuracy and consistency when using brass that has previously been fired out of the same rifle. The Seater Die is used to crimp and seat the bullet to the desired depth, and it includes a built-in roll crimp feature to secure the bullet in place. This can be especially useful for some rifles and shooting applications where reliable feeding and consistency in cartridge length is critical. Neck Sizer Die with an Expander-Decapping Unit Seater Die with a Bullet Seater Plug Made in USA Component and Caliber Reference Table