The combustion of mixtures of ammonium perchlorate and various inorganic compounds of the following general types was studied: oxides of copper and chromium, oxides of other metals, other perchlorates, other ammonium salts, and darkening agents. The additives were generally added at the 2 and 8 wt% levels. Deflagration rates as a function of pressure (100 less than equivalent to p less than equivalent to 1500 psi) and initial sample temperature (ambient room temperature and 100 degree C), and results from motion picture photography of burning samples are presented and discussed.