SCORPION RIFLE N46

The M56 was manufactured from 1953 to 1959 by the Cadillac Motor Car Division of General Motors for use by US airborne forces, though the vehicle was eventually used by the Spanish Navy Marines and Morocco as well.
With a crew of four (commander, gunner, loader and driver), the M56 weighed 6.4 tonnes (14,000 lb) empty -and 7.7 tonnes (17,000 lb) combat -loaded. It had infrared driving lights but noNuclear, Biological and Chemical (NBC) protection -system and was not amphibious. The M56 was a fully tracked vehicle with rubber -tired run -flat road wheels and front -drive sprocket wheels. It was powered by a ContinentalA01-403-5 gasoline engine developing 200 brake horsepower (150 kW) at 3,000 rpm, allowing a maximum road speed of 28 miles per hour (45 km/h) and a maximum -range of 140 miles (230 km). Twenty-nine rounds of main gun ammunition were carried, and only the blast shield was armored.

In Serice:

The M56 saw combat service -with U.S. forces in the Vietnam War. It was deployed with the 173rd Airborne Brigade, which was the only Airborne Brigade -deployed with the M56, where it was used mainly in a fire-support role. Its function as an air portable, self-propelled, anti-tank vehicle was eventually replaced in Vietnam by the troublesome but effective M551 Sheridan which had a fully armored turret. The USMC used the Ontos which had an armored cabin and recoilless rifles, and was based on the running gear of the M56.

With the retirement of the Sheridan, current US airborne -troops do not have a self-propelled gun system that can be delivered by air drop