These two die-sets are intended for reloading bottleneck cases and consist of a Full-Length Sizer Die with an Expander-Decapping Unit and a Seater Die with Bullet Seater Plug. The RCBS Full-Length Sizer Die brings the case to SAAMI minimum cartridge dimensions. This die sizes the outside of the case de-primes and expands the neck to accept the bullet. The die has vents to prevent case damage caused by trapped air and excessive lubricant. Headspace is held to minimum tolerances to avoid changing the case body length during full-length sizing. The included Seater Die has a built-in roll crimper to secure the bullet at the same time as it's seated/ Standard 7/8"-14 Thread Proprietary Die Steel Set includes Full-Length Sizing die and Bullet Seating Die Sizing die brings cases to SAAMI minimum cartridge dimensions Ships in Green Die Box