The Dillon sizing/depriming dies feature a unique "floating decap assembly" with a snap spring that throws the spent primer off the pin and eliminates the problem of primer "draw back" that often occurs when decapping military brass. The primary feature of Dillon’s size die design the long, tapered carbide ring with a radiused opening remains unchanged.
That radiused opening, and its importance to progressive reloading, is one of the reasons why our seat and crimp dies are better. We found a way of manufacturing these dies that has enabled us to make the lead-in radius even bigger! The bigger radius makes progressive loading with our equipment even smoother but that’s still only a part of the story.