AbstractThe flammability limits and ballistic properties of composite fuel‐rich propellants were studied experimentally, using PBAN/AP propellant formulations. Higher pressure and AP contents as well as smaller AP particle size were found to promote sustained combustion and to increase burning rate. The addition of potassium perchlorate (KP) in place of AP increased the burning rate pressure exponent from about 0.3 to over 0.7 at optimum conditions. Ferric oxide and copper chromite catalysts caused an increase of the burning rate by a factor of 2, while the addition of aluminum powder at the expense of the fuel binder was found to have a remarkable effect on the burning rate with a maximum increase of as high as 5‐f