It had a gasoline fueled Hercules JXD engine and a top speed of about 50 mph. It had a mileage of 8 mpg and it could carry 30 gallons of fuel. The armor on the M3 was from half an inch to a quarter of an inch in almost all areas of the car.
The M3 had a crew of two and it could carry six passengers. It weighed around 11,000 pounds and it had a length of about eighteen feet. The armament consisted of one .30 caliber Browning M1919A4 and one .50 caliber Browning M2HB. There was also a radio area in the rear of the car and all the guns were mounted on skate rails. Only sixty-four M3s were made and they all went into service in the Philippines in 1941-1942.
The M3A1 Scout Car which was much more common began production in 1939. It either had the gasoline powered, Hercules JXD engine or the diesel powered, Hercules DJXD engine. It had a four speed forward, one speed reverse transmission and it had about the same armor as the M3. A new feature that was the main difference between the M3 and the M3A1 was that the M3A1 had an anti-ditching roller which meant that the M3A1 could pull itself out of a ditch. The weight of the M3A1 was around 11,750 pounds and the length was almost the same as the M3 which was around 18 feet. The armament was the same and just like the M3, passengers were issued submachine guns such as the Thompson to defend the vehicle.
The M3A1 had some subvariants, like the M3A1E1. The M3A1E1 was equipped with the Buda-Lanova diesel engine. This allowed it to go 4 mph faster than the M3 and it was mainly used by Soviet forces. The M3A1E2 was only modified to have an armored roof to protect passengers better than the M3A1 or M3. The M3A1E3 never reached production, but it was designed to have a 37 mm gun on it. The M3A1 command car had thicker armor and it offered better protection for the driver and passengers. This model was released to the front lines in 1943.
The M3 Scout Car began production in 1938 and was produced by White Motor Company. Production ended in 1944 and by that time, some 20,000 M3A1s were produced. They were used by American, British, Free French, and Soviet forces. It had fair reputation of mobility, but it still had the flaw of not having a roof to protect passengers. This adjustment came only with the arrival of the M3A2. The M3 Scout Car greatly inspired the design of the M3 Half-Track.