Solid rocket motors for defence applications are hugely varied in nature. There is a need to use different propellants with different energetics and burning rate levels and sometimes it is needed to use aluminium powder in the composition and sometimes it may be desired to avoid aluminium to reduce the exhaust smoke signature in order not to exhume the enemy the launch location. Many of these developments point towards the greater incidence of combustion instability which causes trouble to the performance of the rocket motor. Sometimes the instability causes the rocket motor to blast in the air causing the mission failure. There is an unavoidable need to understand about the combustion instability of solid propellants. If the burning solid propellant is segregated into three zones, the first zone at bottom comprises of the propellant chemistry and the third zone at top comprises of the burnt hot gases. The second zone is where the flame stands and interacts between the rest of the two zones. Pressure coupled combustion response connects the combustion –acoustics interaction and there is a necessity to know about this parameter for each solid propellant in order to alleviate the instability problem. There are many experimental techniques reported in literature, of which, the focus of work is to develop T-burner and Impedance Tube techniques and to measure the pressure coupled combustion response of various industrial-grade solid propellants at different initial temperatures, at different pressures and at different acoustic frequencies. These combustion response results will be utilized in the stability prediction programme available at DRDL to predict the stability margin of the rocket motor. It is believed that a plateau-burning propellant with very close to zero pressure index would respond very less to the imposed pressure oscillations and thereby a solid rocket motor which is less prone to combustion instability could be achieved.