M50 Ontos

The impressive-looking M50 Ontos had to be reloaded from outside of the
vehicle.

Designation: M50 Ontos
Classification Type: Tank Destroyer
Contractor: Allis Chalmers - USA
Country of Origin: United States
Initial Year of Service: 1955
Number Built: 294

The impressive-looking M50 Ontos (in the Greek meaning "The Thing") was
built to a United States Marine Corps tank destroyer specification. With
five prototypes built, and each fitted with differing calibers of recoilless
rifles, the T156 design was born. No fewer than 24 of the type were ordered
for further trials, each armed with six of the powerful 106mm recoilless
rifle type. From the T156 trials emerged the T156E2 which gave rise to the
production M50 - each slightly modified from the predecessor. A switch to a
Chrysler-based petrol engine produced 294 models of the M50A1 series, which
in itself included evermore modifications to the system.

At it's core, the M56 was fitted with a common turret mounting six of the
M40A1C recoilless rifles. Additionally, the top four 106mm mounts were
fitted with 4 x 12.7mm (.50 caliber) heavy machine guns to act as spotters
when aligning the main guns. The use of the spotting machine guns was
directly after optical sighting was completed. The spotter machine guns were
then fired to accurize contact. Shortly thereafter, the recoilless rifles
could be fired with some degree of accuracy.

All weapon systems on the M50 were limited in ammunition-carrying
capacities. The 106mm recoilless rifles were limited to just 18 projectiles
spread across the six guns. The 12.7mm spotting machine guns were limited to
just 80 rounds of ammunition. Not to be left high and dry against advancing
enemy infantrymen, an additional 7.62mm machine gun was mounted to the top
of the turret for self-defense.

Besides the limited ammunition situation, crew quarters once inside the
machine were cramped at best. Additionally the weapon systems could only be
reloaded from outside the vehicle, exposing the crew to dangerous enemy
fire. The system saw action in South Vietnam and in the hands of the United
States Marines. No longer in service with the Marine Corps, no replacement
vehicle was selected to succeed the M50 Ontos on the modern battlefield, the
assumption being that other weapon systems are more likely up to the task of
tank destroyer than a similar self-propelled recoilless rifle design like
the Ontos.

Variants:
T165 - Trial Vehicles of which 24 were produced; fitted with 6 x 106mm
recoilless rifles.
T165E2 - Modified and improved T165 models.
M50 - Production Model Designation
M50A1 - Modified M50 Variant; fitted with Chrysler petrol engine over the
original General Motors.

Specifications: M50 Ontos
Dimensions:
Length: 12.53ft (3.82m)
Width:8.53ft (2.60m)
Height: 6.99ft (2.13m)
Performance:
Speed: 30mph (48km/h)
Range: 149miles (240km)

Structure:
Accommodation: 3
Weight: 9.5 US Short Tons (8,618kg)
Systems:
NBC Protection: None
Nightvision: None
Power:
Engine(s): 1 x General Motors Corporation Model 302 petrol engine generating
145hp.

Armament & Ammunition:

6 x 106mm Recoiless Rifles
4 x 12.7mm Machine Guns

Ammunition:
18 x 106mm projectiles
80 x 12.7mm machine gun rounds.