Lyman Pro Dies set a new standard for reloading die performance. Designed for the tremendous volume of their Mark 7 presses every aspect of these precision dies was carefully engineered for top performance. Of course they work great in regular progressive presses as well as turret and single station presses.Lyman size seat and crimp dies are all made of stainless steel which was chosen for its toughness and anti-corrosion qualities. Sizing dies are equipped with highly polished carbide rings for the ultimate in wear resistance and reduced sizing force. In addition the sizing dies are equipped with a spring-loaded decapping rod system to ensure that the primer is forcefully ejected from the primer pocket.You get their famous M die neck expander with its two step expander plug for just the right amount of neck tension and case mouth flare. The pistol sets include their flare die which is designed to allow bullets to properly sit on the case mouth prior to seating.Next is the Micrometer Seating die. This seating die has a micrometer adjustable seating head for precision bullet seating length. Its floating bullet seating punch centers the bullet on the case and eliminates excessive run-out. Finally each set is equipped with a taper crimp die to fully remove any case mouth flare and to provide improved bullet retention.