Semovente L40 da 47/32

By 1942 the Regio Esercito had a problem it could state precisely. Its standard anti-tank weapon, the Cannone da 47/32 Mod. 1935, was a towed gun: once the shooting started it could not be moved, and a towed gun that cannot move is a gun that gets found. What the army wanted was the same weapon on tracks, able to shoot and then leave.

The chassis it got was the one nobody else wanted. The L6/40 light tank was obsolete before it entered service — six tonnes, a 20 mm cannon, and no useful role on a battlefield that had T-34s on it. Removing its turret and building an open box in the space left a vehicle of 6.8 tonnes carrying a 47 mm gun: the Semovente L40 da 47/32, the smallest self-propelled gun Italy built.

The gun is the whole story of the vehicle, and the numbers are unforgiving. The 47/32 firing armour-piercing shot defeated about 31 mm of plate at 800 m, and 47 mm at 100 m, measured against armour set at 30°. Against the light and medium tanks of 1940 that was adequate. Against the tank the L40 was actually sent to fight it was not: a T-34’s glacis was 45 mm set at 60°, which presents about 90 mm of steel along the path of an incoming shot. The arithmetic does not need interpreting.

There was supposed to be an answer. EP and EPS hollow-charge rounds were developed for the 47 mm, and a shaped charge does not lose penetration with range — the same chemistry that made the Semovente 75/18 dangerous in the desert. For the 47/32 it never arrived in quantity: the rounds stayed rare, and Italian sources record that where they were available they were not favoured, their performance being close to that of the ordinary armour-piercing shot. The crews went to the Don with the shot they had.

The first vehicles completed went east. The XIII Gruppo Squadroni Semoventi Controcarri of the 14° Reggimento “Cavalleggeri di Alessandria” left for the Eastern Front on 3 August 1942 with 31 Semoventi L40, attached to the 3ª Divisione Celere “Principe Amedeo Duca d’Aosta”, and took position on the Don with the Italian Eighth Army.

When the Soviet winter offensive came, the group fought and was destroyed. All 31 vehicles were lost. An open-topped six-tonne box with 30 mm of frontal plate and a gun that could not penetrate the armour it was shooting at had no way of surviving a breakthrough by massed T-34s in open country, and it did not.

In North Africa the L40 went to the Ariete and Littorio divisions and fought through to the fall of Tunis in 1943; in July of that year it was in Sicily against the landings. In these theatres one quality that had not been a design goal began to matter: the vehicle stands 1.63 m to the top of its fighting compartment — lower than a standing man, and 22 cm lower than the Semovente 75/18.

A gun that cannot defeat frontal armour can still defeat a flank, and a vehicle that is hard to see gets to choose which part of a tank it shoots at. Used as an ambush weapon from a sunken road or a wall, the L40 was a genuine nuisance. Used as its designation suggested — as something to place in the path of enemy armour — it was a death sentence for its three men.

The command version is the detail that says most about how these vehicles were used. The Semovente L40 comando carried long-range radio sets and map tables for the battery commander, and had no main armament: there was no room for the gun, the radios and a commander trying to run a fight.

Rather than send it out visibly unarmed, the designers fitted an 8 mm Breda machine gun in the gun mounting and shaped it to resemble the 47 mm at a distance. What the vehicle actually carried into a fight was the radio: long-range sets for the battery commander, and the map tables to work them on.

The armistice of 8 September 1943 turned the vehicle against the army that had bought it. On 10 September, in the fighting for Rome, the defenders holding the line along the Via Ostiense and at Porta San Paolo included the remnants of a self-propelled gun squadron with an L40 among them — Italian crews firing 47 mm shot at German paratroops in the streets of their own capital.

The Germans took over what was left. 78 vehicles entered German service as the StuG L6 mit 47/32 630(i), and production continued under German control into 1944; the total built is given as anywhere from 355 to 402, depending on the source and on which variants are counted. Others ended up with Yugoslav partisans and with Slovene and Croat formations, fighting on into a war that had stopped being the one they were built for.

The Semovente L40 is usually filed as a failure, and by its own designation it was one: a semovente controcarro that could not reliably destroy the tanks it was named after. But the judgement is easier than the history. The vehicle was ordered because Italy had a chassis already in production and a gun already in the inventory, and putting the two together took months where a new design would have taken years.

That is the same reasoning that produced the German Marder series in the same months, and Italy improvised as quickly as Germany did. The comparison is fair in every respect but the one that decided whether a crew lived: the Marder’s 7.5 cm PaK 40 is credited with 82 mm of penetration at 1,000 m, the L40’s 47/32 with 31 mm at 800.

• Nicola Pignato, Italian Armoured Vehicles of World War Two (Squadron/Signal).
• Filippo Cappellano & Pier Paolo Battistelli, Italian Light Tanks 1919–45 (Osprey, New Vanguard).
• Nicola Pignato & Filippo Cappellano, Gli autoveicoli da combattimento dell’Esercito Italiano (Ufficio Storico dello Stato Maggiore dell’Esercito).
• Giorgio Scotoni, L’Armata Rossa e la disfatta italiana 1942–43 (Panorama) — for the destruction of the Italian units on the Don.