ONTOS (M50A1) - LLE you remember this monster?

ONTOS (M50A1) - LLE you remember this monster?

(by Michael Scudder)
Ontos means "the thing" in Greek. As applied to the Marine's armoured vehicle, it could mean "the rare thing". This armoured vehicle made significant contributions to the success of Marine and Army infantry operations in Vietnam, but less is known about the vehicle than any other armoured vehicle produced by the US military. Even among military vehicle collectors, the name Ontos often draws blank expressions.

The reasons may stem from the fact that the Ontos was produced in small numbers. Only 176 vehicles are known to have been in the Marine Corps at the start of the Vietnam War. Another factor is the Marine Corps quickly disposed of the surplus vehicles; removing much of the hulls and gun mounts. With so few examples of surviving Ontos making it into the hands of museums and collectors, its story didn't get told. There are more surviving WWI tanks today than Ontos.

OVERVIEW
The Ontos was a relatively light weight tracked armoured fighting vehicle that was designed in the early 1950's to destroy the main battle tanks of this era using the firepower from its six 106mm recoilless rifles. Its diminutive size, 12 ½' long, 8 ½ ' wide, crammed three crewmembers into a compartment slightly higher than 4'. It served the US Marines from 1956 until the bulk of them were dismembered in 1970. Its service to the Marine coincided with the Corps's use of the 106mm recoilless rife.

The Ontos would be more than 10 years into its life cycle before it would be tested under fire. The first test would be against the Dominican rebels in April of 1965. The second test was in the environment of Vietnam; and its role would have no relationship to what was originally intended for this fast little tank killer.

If it is true that an army fights its present war with tactics and equipment from its last war; then it is the mark of a successful army to be able to adapt in order to accomplish the new mission. The Ontos and its crews had to convince the Marine Corps leadership that this fighting vehicle had a role in Vietnam. The success, at convincing its leaders of the Ontos's potential, is mixed. The men that made up the Ontos crews attest that it was only at the company level that they convinced leadership of the enormous firepower that could be available to the grunts; firepower that could change the outcome of a fire fight.

I am struck at the similarities of the Ontos's role within the Infantry Company and the role of the little Stuart tank used by the Marines in the pacific battles of WWII. Both were lightly armoured and vulnerable to the destruction by weapons above 50-caliber. Both of these vehicles were effective because they were small yet could carry relatively high firepower into an infantry fire fight. Their size allowed them to go into areas the larger tanks could not.

The 20" wide tracks of the 9-ton Ontos would allow it to go on the soft soils surrounding the rice paddies of Vietnam. They both served as bunker busters. Both vehicles lessened the infantry's causalities by being close to the fight; and could be quickly deployed to overcome an enemy's fixed positions.

The Ontos carried the beehive round that sent out a hundred darts per firing to clean out a jungle of its enemy. There was no other weapon that could clear a jungle for a depth of a ¼ mile like the 106mm recoilless rifle using the beehive round. Artillery shells and bombs effectiveness was cut to the area of a direct hit.

The jungle vegetation absorbed both concussion and fragmentation. The other vehicles that mounted the 106mm recoilless rifle were open to enemy small arms fire. The Ontos could expose itself to enemy small arms for the short time it took to empty its 6 guns and depart to a more secure position to reload. It was an armoured shotgun and the North Vietnamese Army feared it.

It is no surprise to the veteran of any country's army that weapon systems get misused, unsupplied and/or forgotten by the generals that demanded their development. The Ontos fell into this grouping. Deployment of the Ontos seemed like an after thought to many commanders and the Ontos's parts replacement was a serious concern. It is a testament to the men that manned this small armoured fighting vehicle that some important history was written by its participation in Vietnam.

The Ontos was designed in another era for another purpose. Developed to kill tanks; the Ontos found itself outmoded before it was in the hands of its first crewmen. It was left to the men who manned the Ontos to reinvent it; and they reinvented it into a weapon that served the Marine infantryman.

8 Comments

5 years 13 weeks ago, 3:29 PM

LLE

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but I could not figure how they operated all those recoilless rifles the way they were mounted.

Too old to fight, Too old to run, guess that's why I carry a gun! "would someone show this asshole the way out of town".[Rabbi Avram Belinski-aka "The Frisco Kid"]
5 years 13 weeks ago, 3:32 PM

ivantank

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i want one

i am gonna git me one of these things and put it in my yard..4real

I have reasons for the things I do, just don't expect them to be reasonable
5 years 13 weeks ago, 3:39 PM

LittleDragon

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there are currently no recoiless rifles in all the US Military order of ordnance today ka

Your friend,

LittleDragon

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5 years 13 weeks ago, 3:46 PM

LLE

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There are probably many, more effective shoulder fired weapons avavilable, now.

Too old to fight, Too old to run, guess that's why I carry a gun! "would someone show this asshole the way out of town".[Rabbi Avram Belinski-aka "The Frisco Kid"]
5 years 13 weeks ago, 4:04 PM

LittleDragon

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it is even inexplicable as to why there are no recoiless rifle in the US MiliTARY inventory,but all have been replaced by more modern weapons. it seem that the whole concept of the recoiless rifle is judged to be too dangerous for military personnel. ryo is not sure of why this is, but am only sure that all of the recoiless rifles have been removed from the order of ordnance in all the US military. would you care to comment further ka.

Your friend,

LittleDragon

Moshi Moshi from LittleDragon
5 years 13 weeks ago, 4:44 PM

runawaygun762

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The 84mm M3 MAAWS (Medium Anti-Armor Weapon System) is still in use by the US Army Rangers. It's more commonly known as the Carl Gustav, made by Saab Bofors. It's a ridiculously loud weapon system, but has proven very effective as a "bunker buster" or a great way to clear a small house.

"I have always been a soldier. I have known no other life. The calling of arms, I have followed from boyhood. I have never sought another." From The Virtues of War, by Steven Pressfield.
5 years 13 weeks ago, 6:09 PM

LLE

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the designers paid more attention to Human Factors, despite the loudness. It looks like it is very accurate and much easier to handle than the original 57mm, and the round seems very powerfull.

Too old to fight, Too old to run, guess that's why I carry a gun! "would someone show this asshole the way out of town".[Rabbi Avram Belinski-aka "The Frisco Kid"]
5 years 12 weeks ago, 1:40 PM

ONTOS66

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ONTOS

LLE, regarding the operation of the 106mm Recoilless Rifles on the Ontos (M50 & M50A1):

The 106mm rifles, two inboard .50 cal. spotting rifles and the M1919A4 .30 cal. machinegun were all boresighted to a single gunners sight.

The breaches on the rifles were closed manually to "half-cock" when the guns were loaded and then fully closed hydraulically by a hand pump from the Ontos Commander / Gunner position in the vehicle prior to firing. The firing system was electro-mechanical and controlled from a firing panel at the Ontos Commander location. Guns could be selected to fire individually, in pairs, or all 6 at once.

Elevation and traversing were manual controls for the Ontos Commander. The spotting rifles were also fired by electro-mechanical means as was the M1919A4 machinegun.

The rifles were numbered 1-6 (looking at the rear of the vehicle) from bottom left to bottom right.

The two outboard .50 cal. spotting rifles were only used if guns 2 and 5 were dismounted and used on a ground mount. Ground mounts were not carried on the Ontos for the 106, although each platoon had a couple carried in the M37 3/4 ton truck and trailer which was driven by the attached mechanic when a platoon was deployed with a Battalion Landing Team.

Hope that answered your question.

Semper Fi!

Preston Sewell CPL, USMC 0353 RVN 1965-66
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