Plate impact experiments were performed on commercial alumina disks (AD‐85, manufactured by Coors), with in‐material Manganin gauges, in order to determine the dynamic response of this material in the 0–100 kb range. The measured stress signals showed that the transmitted waves, at the high stress range, are composed of an initial elastic jump, to about 60 kb, followed by a dispersive rise to the final stress level. This behavior was found recently for pure alumina but not for AD‐85. We used the gauges to determine the Hugoniot curve of AD‐85 in the 0–100 kb range and its spall strength in this region.