The main armament consists of a 155 mm/52 caliber ordnance with a maximum firing range of 40 km. The K9 Thunder has a maximum rate of fire of 6 rounds per minute and is capable of multiple-round simultaneous-impact firing. It is able to fire three rounds in 15 seconds, each in different trajectories, so that all of the shells arrive on target at the same time. Sustained rate of fire is 2 rounds per minute. It is compatible with standard NATO 155-mm ammunition. Maximum range of fire is 30 km with standard HE projectile and 40 km with rocket-assisted projectile. After receiving a fire command, the K9 thunder is able to fire on a target within 30 seconds at emplacement and within 60 seconds from movement. Even though TOT (time on target) firing may be accomplished by several howitzers simultaneously, the K9 thunder is able to more efficiently accomplish the same task by simply changing its fire data. The K9 thunder alone can produce three times as much as the M109A2 155mm SPH in firing capability.