The Ontos, officially the Rifle, Multiple 106 mm, Self-propelled, M50, was an American light armored tracked anti-tank vehicle developed in the 1950s. It mounted six M40 106 mm recoilless rifles as its main armament, which could be fired in rapid succession against single targets to guarantee a kill. It was fased out of service in the mid 1990's but re-introduced in 2060 to supress riots.
The Ontos (Greek for "the thing") project was created to be an air transportable tank-destroyer capable of being lifted by the cargo aircraft of the 1950s. The vehicle mounted a cast steel turret with two arms holding three rifles each. This early model could traverse the turret only about 15 degrees. A second prototype used a new suspension system including new tracks, and a newer turret with about 40 degrees traverse. Four of the rifles also had 50-caliber spotting rifles attached, firing a round that flew like the 106 mm round and gave off a puff of smoke on impact with the target. This meant that the 106 mm recoilless rifles were lined up with the target, and then they would be fired. A single .50 caliber machine gun was also carried for anti-infantry use. It saw use in the Indochina war, destroying NVA tanks and structures. After the Indochina war, the Ontos units sat in warehouses unused until their retirement in the 90's. But with riots spreading all over the U.S. during the resource wars era, the M50 was taken out of retirement by the National Guard. The six 106mm recoiless rifles were loaded with special air-burst pepper spray rounds. The .50 caliber spotting rifles were also replaced by laser targeting systems, as to avoid having to fire live .50 cal rounds into large crowds. When fired, the six recoiless rifles produced a massive shockwave, breaking windows, setting off car alarms, and throwing near by pedestrians and rioters to the ground. But that wasn't the worst part, when the six pepper burst shells flew over the crowd, they exploded sending pepper gel in all directions. While it was very messy, the M50 riot controll units could disperse crowds of hundreds in a single volley. During the Invasion of Alaska in 2066, M50 Ontos units were deployed to the front lines to slow the advance of Chinese tanks. M50s arrived before M-75 and M-56 units, and managed to not only slow, but stop the Chinese advance all together. Chinese tank crews didn't know what hit them. One moment there are 30 tanks rolling across the tundra, one minute later, they're all on fire. The M50 would be further used in the pasification of Canadan citizens and as a tank destroyer in Asia.
On October 23rd, 2077 the world was consumed in nuclear fire. With the M50 mostly being used by the national guard, most remained in Canada and China. In the 18 months following the war, these survivors would find a new home in the official U.S. Military Remnant. Generally deployed along side M28 and M41 tanks, the M50s would live on for many years to come because of their nuclear powered engines. At least one was used by the settlement of Rockvale in China, to defend against local warlords.