In a systematic study to compare the effects of the values of burning rate and pressure exponent in RDX-AP based composite propellant, various compositions with varying percentages of zirconium carbide (ZrC) and zirconium silicate (ZrSiO4) were formulated to select a suitable candidate. Various rocket parameters of each formulation were theoretically predicted by the NASA CEC-71 program and the burning rate was evaluated in pressure range of 3-11MPa. In addition, density, sensitivity, and thermal properties of compositions having maximum effects on pressure exponent's values were also evaluated. It was concluded that ZrSiO4 enhances the pressure exponent n value substantially, whereas ZrC doesn't have significant effects on it as compared to base composition and also provides higher density values of composite propellant formulated.