The Ontos Was America’s Armored Shotgun

Weird little Marine Corps tank blasted North Vietnamese troops


Designed and built in a farm tractor factory and armed with six 106-millimeter recoilless rifles, the M-50A1 Ontos was rejected by the Army and only purchased in small numbers by the Marine Corps. Years later in Vietnam, the USMC trained infantry riflemen to drive these vehicles, nicknamed “Things,” down the roads and into the bush to scare the living daylights out of the North Vietnamese.

Michael Scudder and the veterans of the 1st Anti-Tank Battalion, 1st Marine Division, and the 3rd Anti-Tank Battalion, 3rd Marine Division, have left us a fascinating body of lore about the development and deployment of the Ontos, which Pres. John F. Kennedy once dubbed a “weird little bugger.” More than just another zany mid-century weapon, the story of the M-50A1 offers a powerful lesson in adaptation.

The Ontos — which actually means “thing” in ancient Greek — was proposed at the end of the Korean War as an air-transportable anti-tank vehicle for the U.S. Army and Marine Corps. As an armored vehicle, the Thing had its charms and its challenges.

“The engine/transmission combination reminded me of the highly modified hydromatic transmissions being used on the drag strips of the early 1960s,” Scudder, a former hot-rodder prior to joining the Marines, noted.

At only nine tons, the Ontos could handle rice paddies and muddy roads with its wide farm-boy treads, and although lightly armored, it was tough enough to take light gunfire while maneuvering to position.

In addition to .50-caliber spotting rifles, each one mounted a remote-controlled .30-caliber Browning machine gun. But it was the six big sticks of whoop-ass that gave the Thing its real teeth.

During acceptance tests at Aberdeen Proving Ground, crews fired all six 106-millimeter recoilless rifles were fired at once — blowing bricks from buildings and windows from cars nearby.

Above — an Ontos at Tet in 1968. Brian Ross photo. At top — An Ontos in Vietnam. Photo via Wikimedia

The track’s interior could barely contain the three Marines needed to drive, load, shoot and command the weapons. Like other lightly armored vehicles, the Ontos was a bad place to be if it struck a mine.

Its tracks were cumbersome to maintain and spare parts were a constant concern. Many Things gave their lives to keep their fellows in the fight.

Then there was the matter of reloading in the field. Harsh language often filled the interior when the loader was ordered out of the vehicle to perform his duty.

Although the recoilless rifles gave off huge clouds of smoke when fired, its employment as a convoy escort and bunker-buster made its visibility less of an issue. Obsolete upon arrival as a lightweight tank-killer, the Ontos marked time in the USMC inventory until 1965 when they were deployed first to the Dominican Republic and then on to Vietnam.

There it was the Marine riflemen and the company-level officers who learned how to use the weird little tank.

“Ontos crews were pulled from the Marine infantry battalions to learn the trades of gunners, radiomen, mechanics and tacticians,” Scudder wrote. “Some crewmen were motor transport or track maintenance trained, but most were more likely to be former riflemen.”

Repurposed in the field, the Ontos became one Hell of an infantry support weapon.

“[T]he beehive round […] sent out a hundred darts per firing to clean out a jungle of its enemy,” Scudder continued. “There was no other weapon that could clear a jungle for a depth of a quarter mile.”

“It was an armored shotgun and the North Vietnamese Army feared it.”

Parked in bunkers at Khe Sanh, the Things had a hand in repulsing a major ground attack. During the Tet Offensive they also proved to be lethal street fighters.

“The Ontos was knocking out NVA positions [in Hue] with each firing,” Scudder added. “They learned that they could force the [North Vietnamese Army] from some of the buildings by firing the M-8 .50-caliber spotting rifle through the windows and thus notifying the NVA that their demise was near.”

“The Ontos did in a short time what the artillery and air units couldn't.”

The grunts’ improvised success with the Ontos echoed an earlier Pacific War adaptation. In 1944, the 776th Tank Battalion transformed itself into a field artillery group to support the assault on Leyte Island in The Philippines.

Amphibious tracked vehicles — better known as Amtracks — equipped with 75-millimeter howitzers provided both direct and indirect fire support to infantry without sacrificing their amphibious capabilities. Indeed, the 776th made both the longest waterborne end-run — 100 miles — and the longest movement across open sea — 38 miles — during the war.

Buy ‘Praying for Slack: A Marine Corps Tank Commander in Viet Nam’

The ultimate proof of a weapon's effectiveness is its impact on the enemy. If Marine commanders had little love for the Ontos, the North Vietnamese had even less. Again and again the Ontos crewmen interviewed by Scudder emphasized the fear the North Vietnamese had of the Thing and the care the guerrillas took to avoid contact with them.

Like old soldiers, the Ontos just faded away. After four years of battle, they were worn out and abandoned by 1970. Some were sold as surplus but most were junked. a very few wound up on display.

Today there are more remaining tanks from World War I than there are Things from the jungle.

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