Firing test of solid rocket motor with pintle-technology carried out and the measured pressure-time curve was compared with the values predicted by the internal ballistic and performance analysis. Without baffle, the measured combustion chamber pressure was similar with the predicted pressure at the beginning of combustion, but gradual increase in pressure, which was unexpected with the end-burning grain of which burning area is constant, was observed. A baffle was inserted to make uniform flow over the pintle. Unlike the thruster without baffle, the measured combustion chamber pressure was 1.4 times higher than the predicted value. Through the CFD simulation, 10% of total pressure loss of the flow was observed from combustion chamber to nozzle throat when the baffle was inserted. The measured pressure with baffle was predicted well by considering the total pressure loss in the internal ballistic modelling and performance analysis.