The 3-Die Taper Crimp Set is for loading straight-wall cartridges. Its steel Sizer Die sizes the case and de-primes. Note: Cases must be lubricated. The Expander Die expands the case to the proper diameter to accept the bullet, and it imparts case mouth flare/bell for bullet feeding. The Seater Die seats the bullet and taper crimps. Features a hardened steel Sizer Die (case lubrication required) Expander Die to properly expand case to accept bullets Taper Crimp Seat Die for Proper cartridge headspacing Comes in a green storage box All RCBS dies are machined to exacting tolerances, hardened and finished to the highest standards in the industry Made in USA