The Lee Precision Powder Through Expanding Die is a specialized tool for reloading .40 S&W and 10mm Auto cartridges that significantly improves efficiency. Its innovative design performs two jobs in one step: it expands the case mouth to allow for easy bullet seating and also lets you drop powder directly through the die. By combining these functions, it saves a station on a turret or progressive reloading press, which speeds up the entire process. When used with a case-activated powder measure, this die helps create a fast, automated system for high-volume reloaders.