The RCBS 10501 is a two-die set designed specifically for reloading bottleneck cases. This set comprises a Full-Length Sizer Die, equipped with an Expander-Decapping Unit, and a Seater Die, complete with a Bullet Seater Plug.The Full-Length Sizer Die ensures the case conforms to Saami minimum cartridge dimensions. It focuses on sizing the case exterior, de-priming, and expanding the neck for bullet reception. The die is vented to avoid any case damage from trapped air or excessive lubrication. It ensures minimum headspace tolerances are maintained to prevent any alterations to the case body length during the full length sizing process.In addition to this, the Seater Die included in the set features a built-in roll crimper. This function ensures the bullet is locked securely into place at the same time it\'s being seated.