RCBS Group D Small Base Die Set 5.7 X 28 FN. It consists of a Small Base Sizer with an Expander-Decapping Unit and Regular Seater Die with Seater Plug. The sizer resizes cases below SAAMI minimums reducing the shoulder and body by a few thousandths. It also de-primes the case. The included Seater Die has a built-in roll crimper to secure the bullet at the same time it's seated. To seat bullets without crimping simply unscrew the die until the crimp ring no longer engages the case mouth. Specifications for RCBS Small Base Sizer Die Set - Group D - Bottleneck Rifle Cartridges: Manufacturer: RCBS Caliber: 5.7x28mm Quantity: 1 Color: Silver Fabric/Material: Steel Gun Type: Rifle Projectile Caliber: .224 Caliber Country of Origin: USA Features of RCBS Small Base Sizer Die Set - Group D - Bottleneck Rifle Cartridges Two-die set for bottleneck type cases used in tight-chambering semi-automatic pump or lever-action rifles Small Base Sizer with an Expander-Decapping Unit resizes cases below SAAMI minimums reducing the shoulder and body by a few thousandths Sizer de-primes the case Seater Die has a built-in roll crimper to secure the bullet at the same time its seated Package Contents: RCBS Small Base Sizer Die Set - Group D - Bottleneck Rifle Cartridges RCBS 11703: Group D Small Base Die Set 5.7 X 28 FN