With the Lyman Hartmetal expander extends the life of the sleeves. Thanks to the special, extra hard and smooth Hartmetal expander prevents stretching and lengthening of the sleeves during the calibration process. Longer intervals can be set until the next trimming of the sleeves. The Hartmetal expander is freely rotatable mounted on the ejector rod, this guarantees exact centering in the sleeve mouth. The Hartmetal expander can be mounted in two positions on the ejector rod, so even very short sleeves can be calibrated correctly. There is an adapter for all common RCBS Matrices included!