Armstrong's mixture

Armstrong's mixture is a highly shock and friction sensitive^[1] explosive. Formulations vary, but one consists of 67% potassium chlorate, 27% red phosphorus, 3% sulfur, and 3% calcium carbonate.^[2][3] It is named for Sir William Armstrong, who invented it sometime prior to 1872 for use in explosive shells.^{[4][additional citation(s) needed]}