The response of a range of ammonium perchlorate–based propellants and a polymer–bonded explosive to drop–weight impact loading has been studied using high–speed photography. This technique allows the generation of ‘hot spots’ and the subsequent growth of reaction to be recorded. In separate experiments, the mechanical properties of these materials were measured over the range of strain rates 0.01−8×103 s–1 using an Instron 1122 and a split Hopkinson pressure bar. In addition, the effect of temperature on their high–strain–rate properties was examined over the range −60 to +60 °C. Scanning electron microscopy studies were performed, on both as–received specimens and material which had been recovered from interrupted drop–weight experiments, to investigate the connection between microstructure and ignition sources. A close link was established between the mechanical properties at the appropriate strain rates and the ignition response to impact.