- World War Two
- U.S. Army
- used M4 Sherman tracks, roadwheels and drive sprocket.
- designed to tow 90 mm anti-aircraft gun / 155 mm gun (M40 Gun Motor Carriage) or 8-inch howitzer (M115 203 mm howitzer)
- rear compartment carried gun crew and other equipment (included a crane to assist with heavier projectiles in late production)
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