Although capable of generating a high rate of fire, autocannons overheat if used for sustained fire, and are limited by the amount of ammunition that can be carried by the weapons systems mounting them. Both the US 25 mm Bushmaster and the British 30 mm Rarden have relatively slow rates of fire so as not to use ammunition too quickly. The rate of fire of a modern autocannon ranges from 90 rounds per minute (in the case of the British Rarden), to 2,500 rounds per minute with the GIAT 30.