Ontos, Greek for "that which is indeed" but commonly more loosely translated as "thing," is an apt nickname for this little vehicle. The .50cal spotting rifles have been removed from this example, but would normally be mounted on the top four 106mm rifles. On the left side of the hull is a mounting bracket for a fuel or water can, and just above and to the rear of that is the left taillight. Visible between the 106mm rifles is the guard for the gunner's M20A3C periscope. In the center of the air intake louvres is the engine access hatch. On the M50A1 this hatch, along with the transmission access hatch just below the air intake grilles, would be louvred as well. (Picture courtesy Armor Foto.)
The driver and commander of this vehicle can be seen at their stations, and the commander's machine gun is uncovered in contrast to the recoilless rifles. The men riding on the rifles are members of the Lebanese Army. (Picture taken in 1958; available from the Marine Corps University.)
The rifle traveling lock is engaged in this imposing view of this beautifully restored machine. It is the bar running across the front of the hull that is attached to the bottom two rifles. The extra louvres on this vehicle are easily contrasted to the vehicles above. The gunner's periscope guard is visible between the rifles, and a machine gun mount is perched on the arm connecting the two groups of rifles.
The beam running along the outside of the suspension was known as the side channel. Along with a spotting rifle, ground mount sighting and fire control instruments were stowed on the rear of the upper left rifle. Stowage for a machine gun tripod is visible just in front of the spare track shoes.
A closeup of the closed driver's hatch is provided here. His periscope is raised, and the gunner's periscope guard can be seen in the background.
The chambers of the right three M40A1C rifles are visible here. The mount for the .50cal spotting rifle is apparent on the outboard recoilless rifle, and the vehicle's exhaust pipe and muffler can be seen running along the side of the hull.
Details of the track and suspension can be seen here. The track has both center and outside guides, and each track is made up of five band-type sections. The rubber torsilastic springs are mounted externally, and have the benefit of being resistant to corrosion. Two of the vehicle's shock absorbers can be seen as well.
Another view of the drive sprocket and suspension is provided here.
The rear double-door hatch is open on this vehicle. Stowage for four recoilless rifle rounds was provided in the rear of the fighting compartment. The first aid kit is mounted on the gunner's seat backrest, and his seat cushion can just be seen to the front of this. The vehicle's radio can be see to the front of the gunner. The driver's position is at the front left of the hull, and the steering brake control levers are visible to his front.
Stowage for eight 106mm rifle rounds was provided beneath the fighting compartment, and access was via this fold-down rear plate.
A closer view of the gunner's controls and periscope mount is provided here.
The driver's instruments are shown here. From left to right, the gauges are as follows: Transmission pressure (above), transmission temperature (below), fuel level, speedometer, battery generator, oil pressure (above), engine temperature (below). The three switches to the front of the image are for the vehicle's lights, and the engine choke knob is just behind the light switch group.
A more detailed view of the commander's machine gun mount is provided here, and the spotting rifles can be seen in the background. Vehicle commander Sgt Franklin Steed was providing cover for Marine Air Group 36 in Vietnam. (Picture taken 24 Jul 1966 by PFC Cowen; available from the National Archives.)
Note that this vehicle only has four recoilless rifles mounted. The rifles are in their travel lock, and the spotting rifles can be seen on the upper 106mm rifles. This crew was part of the III Marine Amphibious Force. (Picture taken 23 Feb 1968; available from the National Archives.)