The Cold War produced a number of unusual weapons systems, and few were more unusual than the M50 Ontos (a Greek word meaning “entity” or “thing”). In the aftermath of the Korean War, The M50 Ontos and its cousin, the M56 Scorpion, were developed to fulfill the role of Tank Destroyers, a service corps left to languish following the end of World War 2. Both the Army and the Marine Corps had been disappointed by their difficulty in stopping Russian made armor in Korea, and the prospect of thousands of Soviet tanks flooding across the plains of central Europe gave rise to the re-establishment of the dedicated tank destroyer concept.

In this New Vanguard edition, author Kenneth Estes describes in considerable length and detail the design evolution of these two vehicles. Neither the Ontos nor the Scorpion were derivatives of the other, but were both developed in parallel. The M56 Scorpion, with its single 90mm gun on a light-weight tracked carriage, was an otherwise conventional vehicle developed by the Ordnance Dept. specifically for use with the Airborne forces, as an air-droppable anti-tank punch for the Army’s quick response troops. The vehicle was tested, and after considerable administrative delays, 160 were distributed for use with the 11th, 82nd and 101st Airborne Divisions.

The Ontos, on the other hand, had a more convoluted development. Army Ordnance had already been working with the Detroit Arsenal to develop a cheap, light weight “infantry support vehicle”, utilizing the new 105mm recoilless rifle (later modified and re-designated as 106mm), that was termed an “expendable item” (I wonder if that applied to the crews, too?). Their efforts were eventually teamed with “Project Vista” scientists and engineers (a California Institute of Technology effort studying methods and strategies for the defense of western Europe) that envisioned a family of small, tracked “infantry” vehicles centered around a multi-barreled recoilless rifle-carrying vehicle. The shaped-charge firing recoilless rifle held great promise as a tank killer, and defense researchers envisioned the Army with thousands of these in fixed positions, in conjunction with millions of mines, defending the edges of Western Europe from the Russian hordes.

Needless to say, the operational outcome didn’t follow the script. Following a lengthy testing phase (and turf wars within the Army hierarchy), the Ontos was eventually judged unsuitable for use. The Army would stick with its jeep-mounted single barrel 106s. On the other hand, the Marine Corps, in an effort to bolster their meager anti-tank resources, accepted the M50 with open arms. The Marines had been an original partner with the Army in wanting a new anti-tank capability, and so integrated the Ontos into their infantry anti-tank units.

The remainder of the volume describes the attributes of the vehicles themselves. Of necessity, their small size made them uncommonly cramped vehicles for their crews, and in the case of the Ontos, the crew had to dismount the vehicle to reload the tubes. Early M50s had some crew members actually riding on the outside of the vehicles. Their only combat use was in Vietnam, where both the M50 and M56 were used as infantry support vehicles. The Army fielded a small number of Scorpions with indifferent results, while the Marines used a limited number of Ontos quite successfully in the 1968 battles of Hue and Khe Sanh. The Spanish Naval Infantry accepted 5 Scorpions for their use, while little is known of the use and outcome of the vehicles accepted by the Moroccan Army. The M56 was eventually replaced by the M551 Sheridan with U.S.Army Airborne forces in the 1970s, and the Marines last Ontos survived at Gitmo until 1980.

Thanks to IPMS for the opportunity to learn more about these two Cold War curiosities, and to Osprey Publishing for providing this review sample.