It is known that short igniter tubes tend to generate a big pressure wave in a large calibre gun chamber. This paper describes an investigation of ignition system to reduce a pressure wave in granular solid propellants. The investigation was carried out with both experimental and numerical methods. Experiments were performed using a combustion vessel with a rapture disk. The test vessel was designed to measure the pressure wave at the initial combustion of granular propellants in a relatively simple manner. Several igniter tubes were mainly evaluated in the experiments, especially a unique igniter tube in which flash holes were designed on the top of the tube. From the experimental results, it was verified that the negative differential pressure were reduced by using the unique igniter tubes. In addition, the effects of the igniter tubes were analysed with an interior ballistics simulation code based on two-phase reactive flow model.