Antimony trioxide, lead chromate, and copper antimonite are suitable oxidants for silicon metal in time-delay compositions ignitable by shock tubing. Measured burn rates for these systems vary from 6 to 30 mm/s. Lead chromate mixtures burned fastest under comparable conditions. The latter two systems show a bimodal burn rate versus silicon content dependence with a local minimum in burn rate at about 35 mass% silicon. Addition of aluminium powder or fumed silica reduces burn rate. Copper antimonite-zinc antimonite coprecipitates provide for faster burning than neat copper antimonite-silicon mixtures.