The dynamicb1&rlarr2;b2 phase transformation of KCl was investigated in a series of plane wave experiments. Commercial Manganin gauges, used as in‐material stress gauges, recorded stress histories of the shock loaded KCl specimens. Using calibration curves for the gauge’s response under shock loading and unloading the values of theb1&rlarr2;b2 transformation stresses were determined. It was found that theb1→b2 transition is at 2.34 GPa while the reverseb2→b1 transition is at 1.61 GPa. These values are in good agreement with values given by other workers using static and dynamic methods.