One of the critical factors influencing the successful launch of a missile is the operating pressure of its rocket motor. The observation has been made that the size and variations of the nozzle throat, attributed to erosion caused by the burning of the propellant grain which generates combustion gases, play vital roles in this regard. The current research is focused on evaluating the erosion rate in the nozzle throat, considering variations in the propellant components and the utilization of an energetic propellant. The method of propellant grain burn-back is numerically employed to determine the erosion rate in both Nitramine and non-Nitramine propellants. Subsequently, the results are compared with experimental outcomes. The maximum volumetric impulse, a fundamental parameter in energy production, will be achieved by employing low binder and high aluminum percentages in the propellant. If 12% of a solid explosive such as HMX is added to the composite solid propellant, the erosion rate of the throat area is almost decreased by 25%. Based on the assumptions, the error from the numerical and experimental solutions was less than 12% when compared.