SPAT the Scorpion

Here’s one of my favorite types from the “long forgotten” fighting vehicle files – the M-56 Self Propelled Anti-Tank (SPAT) Gun, nicknamed the “Scorpion.”

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M-56 Scorpion - Front Quarter

This example was on display at the Infantry Museum at Fort Benning (the museum has since relocated, and I don’t know if they have moved all the outdoor exhibits yet).  First impression …. is this really a fighting vehicle?  Looks more like a toy.  Despite the looks, this tracked vehicle was rather formidable in its day.

The Army developed the M-56 based on post-World War II requirements for a light anti-tank weapon for airborne forces.  Everyone recalls the limited effectiveness of the bazooka on German Tiger tanks.  Post war, the Army feared more potent Soviet tanks would blunt airborne operations.  In the late 1940s and early 1950s, towed anti-tank guns capable of dealing with heavy tanks weighed too much for light infantry use.  ATGMs, while promising, were still in development at that time.  One option was a lightweight anti-tank gun carrier – an extreme version of the World War II tank destroyer.

Designers built the M-56 around a 90mm gun, which for all purposes was the same gun arming contemporary M-47 medium tanks.  Following every effort to save weight, the Scorpion offered no protection for the crew save a blast shield around the gun.  Note the bare metal seat above the equipment bin, just below the gun.  Had to be good for the old fourth point of contact!

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M-56 Profile

All dressed out, the M-56 weighed just over 7 tons.  A 200-hp gas engine gave it a road speed of 28 mph.  Note the road wheels in the side view.  Those are pneumatic run-flat wheels, which no doubt eased the ride for the crew of four in the bare metal seats.

The M-56 carried 29 ready rounds into action, stowed in tubes under the gun.

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Ready Rounds

The obvious drawback was lack of crew protection.  Also with a powerful gun on a light chassis, the M-56 kicked considerably, requiring some forethought in weapon placement.

But the Scorpion was what the Army needed at the time – a light weight anti-tank system capable of supporting airborne operations.  Cargo planes of the day could handle the light load.  As seen in this clip, the M-56 required six chutes.  Watch the drop:


The M-56 entered service in 1953 with the 82nd and 101st Airborne Divisions.  The 173rd Airborne Brigade used the Scorpions in Vietnam.  But by the late 1960s, the multi-purpose M-551 Sheridans supplanted the M-56 in the airborne units.

Now before we go off criticizing the 90mm SPAT as a bad weapon system, consider the time frame and technology.  Further consider the opposition, over behind the Iron Curtain, were fielding things like the ASU-57 and ASU-85.  So if our weapons were silly, we were all silly together!

More photos of the M-56 are at David Lueck’s walk around page.

8 thoughts on “SPAT the Scorpion”

  1. I can’t tell you what a pleasure it is to open the blog and find my associate Craig has posted an interesting piece.

    **nudges Craig and whispers “Ontos!”**

    1. Well, as I say, “One option was a lightweight anti-tank gun carrier.” Another was, as you allude to, a lightweight vehicle with recoilless rifles.

      Me needs to visit the USMC Museum at Quantico for to collect some good imagery. They have an M-50 on display there.

  2. I was surprised to find the Armor Center is moving to Benning. While the Patton Museum is staying at Knox, it will changed quite a bit. The Armor museum is also moving to Benning. I’m guessing the movement of the Infantry Museum is a result of the Armor move to Benning.

    I’m guessing a few Blue Legs are spinning in their graves over this.

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