Lyman Neck Expanding Rifle M Die for .25-20 Winchester 7342089 The Lyman Neck Expanding Rifle M Die for .25-20 Winchester improves accuracy of cast and jacketed bullet reloads. It doesn't stretch cases like standard expander button style dies do. It works in a two-step process; the first step expands the inside of the case neck to just under bullet diameter, the second step expands the case mouth to bullet diameter or slightly over, so that the bullet can be started perfectly centered. Specifications: - Compatibility: .25-20 Winchester - Material: Steel