Redding straight wall expander dies are equipped with a neck expander plug designed for use prior to the bullet seating process. These expander dies slightly flare the case mouth to facilitate bullet seating. Constructed from the highest quality alloy steels available, they are machined on hardinge super-precision lathes, which are capable of maintaining the industry's tightest tolerances. The dies undergo heat treatment in atmospherically controlled furnaces and are hand-polished to ensure smooth and flawless operation. As a result, these dies are engineered to maintain tolerances and provide a lifetime of reliable performance.