Infantry support guns or battalion guns are artillery weapons designed and used to increase the firepower of the infantry units they are intrinsic to, offering immediate tactical response to the needs of the unit's commanding officer. They typically have short, low-velocity barrels, and light construction carriages, allowing them to be more easily manoeuvred on the battlefield. They are generally used for direct fire, rather than the indirect fire of other types of artillery. Their role has generally been replaced by tanks using tank guns, infantry fighting vehicles using autocannons, other combat vehicles, mortars, recoilless rifles, rocket-propelled grenades and shoulder-launched missiles.