M109 Paladin

The M109 is an American 155 millimeter self-propelled howitzer mounted in a fully rotating armored turret on a tracked chassis, introduced in the early 1960s to replace the earlier M44 and M52 self-propelled guns as the standard indirect-fire artillery vehicle of American armored and mechanized forces. Operated by a four-person crew consisting of a commander, driver, gunner and ammunition handler, the M109 combines its main gun's firepower with enough armor and mobility to move and fire alongside the tanks and armored fighting vehicles it supports, rather than trailing behind as a towed gun would. First fielded during the early Cold War, the M109 has been continuously modernized through several major variants over more than six decades, with the current M109A7 version remaining in active frontline service, making it one of the longest-serving self-propelled artillery systems still in use by any military in the world.