Squads, sections, and crews generally are the smallest organizations in tactical units. While size can vary greatly, most range from four, as in a tank crew, to ten or twelve soldiers, as in a rifle squad or mortar section. Generally, Staff Sergeants are the leaders of squads, sections, and crews.
A tank is a crew-oriented system. For the tank to be an effective weapon system, the four crew members must know their jobs, and know them well. If one fails, the tank fails. Armor crew training emphasizes hands on work. Crewmen now get five times more driving than they did before January 1977. Gunners and loaders get nearly three times more practice in their jobs. Innovative techniques such as sub caliber and laser firing enhance hands on training. Turret trainers and driver simulators supplement actual tank use to reduce costs.
The Field Artillery Cannon Crewman serves in a variety of assignments worldwide. He is the base of the Field Artillery, manning light artillery in Airborne, Air Assault and other light units, crew on the M109A6 PALADIN Self Propelled Howitzer, or "humping joes" in ammo sections.