The Tank Destroyer Command requested a vehicle that would be a command car, personnel and cargo carrier, and a AA multiple MG mount. The design took the turret off the M8 and had an open vehicle with a centrally mounted .50 cal MG for AA protection. The ring mount was a type M66.
Standardized in April 1943 as the Armored Utility Car M10. But to avoid confusion with the M10 tank destroyer it was changed to the M20.
Based on the M8 chassis. There were 2 wood bench seats and a rear seat for the crew. The right sponson had the radio and a map table was at the front.
Was intended to be used by commanders of mobile units and had command radio sets installed.
The engines were in the rear with fans blowing to the rear, the M20 was often able to sneak up on opposition.
Could carry a bazooka and 5 .30 cal carbines. The bazooka fired a 3.41 lb round at a velocity of 300'/sec.