a German soldier sits on the armour of a Semovente M43 da 105/25 — or Sturmgeschütz M43 mit 105/25 853(i); it is interesting that the vehicle still carries its original Italian camouflage and registration number, yet the drive sprocket already has the additional large teeth — suggesting the Germans had these fitted even to some already-completed vehicles, source: Worldwarphotos.info with the permission of the site operator, edited

A more powerful gun is needed

By mid-1942 the Italian army had accumulated sufficient practical experience with the Semovente M40 da 75/18 in combat to assess the vehicle's strengths and weaknesses. On the whole, the Ansaldo vehicle had proved itself on the battlefield. A second generation — the M41, with a more powerful diesel engine — was already in production, and a third generation, the M42 with an even more powerful petrol engine, was already being planned. The self-propelled gun had shown itself to be a reasonably versatile fighting machine, capable of functioning not only as an infantry fire support vehicle but also as a tank destroyer when using shaped-charge ammunition. At the same time, however, combat experience had also revealed its shortcomings. The problem of the weak engine was already being addressed through the development of the second and third generations, but considerable room for improvement also existed in the area of armament.

The self-propelled gun was armed with only a light 75 mm howitzer with a barrel length of 18 calibres. This weapon excelled neither in destructive effect against soft targets — its small calibre meant low shell weight — nor in penetrating the armour of enemy fighting vehicles, where it was hampered by weak ammunition, a short barrel and correspondingly low muzzle velocity. With increasing target range, the weapon also lost accuracy fairly quickly. It is therefore no surprise that the first project to rearm the Semovente with a more powerful gun emerged as early as 1941, eventually leading to the vehicle known as the Semovente M42M da 75/34, with a gun of 34 calibres length (75 mm × 34), far more effective against armoured targets.

The army had come to realise, however, that it also needed something a little different — a self-propelled gun that could not only destroy modern enemy tanks but also provide infantry with fire support far more effectively than the 75 mm gun was capable of. This was to be achieved by using a weapon of larger calibre. In that same mid-1942 period, the Italian army therefore issued a competition for the development of a new self-propelled gun with a 105 mm gun. Ansaldo — the supplier of the existing Semovente da 75/18 — naturally entered the competition immediately, proposing to use its proven existing design as the basis for the new vehicle. The firm OTO (Odero-Terni-Orlando) also entered, however, proposing an entirely new vehicle based on the chassis of the heavy tank P26/40, then still under development. Its main armament was to be the Obice da 105/23 Mod. 1942 howitzer, developed by OTO itself.

an American soldier beside the abandoned wreck of a Sturmgeschütz M43 mit 105/25 853(i); the four large teeth added to the drive sprocket as a measure against track slipping are clearly visible here, source: Worldwarphotos.info with the permission of the site operator, edited

Ansaldo had, however, a considerable advantage over its competitor. Its self-propelled guns were already in series production, while the heavy tank P26/40 was still in the development and refinement phase. Ansaldo could therefore prepare a prototype relatively quickly and also promise a very early start to production. There were further advantages as well. A self-propelled gun based on the existing Semovente would certainly be much lighter and cheaper to produce than a vehicle based on the heavy tank chassis. Moreover, crews and mechanics already had considerable experience with Ansaldo's vehicles. The choice between the two proposals was presumably not a difficult one.

Prototype and series production

Ansaldo delivered its prototype in the second half of January 1943. Although the Semovente M42 served as the starting point, fairly substantial design changes were incorporated. First, the chassis had to be lengthened by 40 mm and widened by as much as 170 mm to accommodate the more powerful weapon. The designers nevertheless managed to reduce the vehicle's overall height by approximately 100 mm. The engine section was also shortened by 200 mm, which allowed the fighting compartment to be correspondingly lengthened. Further changes included the hull's front wall, which was now formed by the junction of two flat plates rather than a single curved one. As a result of all these modifications the vehicle earned its own designation, M43 — though the designation M42L is also apparently sometimes used, the L standing for Lungo, meaning "long". The new front hull configuration, as well as the different proportions of the older Semovente M42 with its 75 mm gun and the new M43 with its 105 mm howitzer, are clearly visible in the photographs HERE and HERE.

Prototype trials began in February 1943. The army's representatives were evidently satisfied — when it came to the armament itself, they were reportedly very satisfied with its performance. Following the completion of testing, an order for 130 series vehicles was placed on 29 March 1943 under the official designation Semovente M43 da 105/25. Production was carried out by Ansaldo — or more precisely in its subsidiary Fossati plant in the Genoese suburb of Sestri Ponente.

an Allied soldier beside a knocked-out Sturmgeschütz M43 mit 105/25 853(i); the Nebelkerzenabwurfvorrichtung smoke discharger bracket is clearly visible at the rear of the vehicle, source: Worldwarphotos.info with the permission of the site operator, edited

Design description

The running gear of the Semovente M43 remained identical to that of the preceding M42 — and the even older M41 and M40 generations. The vehicle therefore had eight small-diameter rubber-tyred road wheels on each side. Each wheel consisted of two discs, with the track guide teeth passing through the gap between them. The road wheels were paired on shared bogies, and two adjacent bogies were suspended from a shared swing arm sprung by a large leaf spring. With eight road wheels, this meant four bogies and two swing arms with springs. The running gear also included a front drive sprocket, a rear idler wheel and three return rollers supporting the upper run of the track.

The vehicle was powered by the FIAT-SPA 15TB Modello 1942 petrol engine with a displacement of 11.98 litres and an output of 190 horsepower at 2,400 rpm. The rear-mounted engine was coupled to a five-speed FIAT gearbox located at the front of the hull. The Semovente M43 da 105/25 weighed 15.8 tonnes — figures of 15.7 and even 16.0 tonnes are also cited — its maximum road speed was around 35 km/h (40 km/h according to some authors), and its range was approximately 180 km. The armour plates of the hull and fighting compartment were partly riveted to a load-bearing frame and partly welded. The front armour of the hull consisted of upper and lower sections. The upper, more exposed plate was 50 mm thick, while 25 mm sufficed for the lower one. The front wall of the fighting compartment, by contrast, was a respectable 70 or 75 mm thick — depending on which source one consults. The side walls of the compartment were 45 mm thick and the rear wall 25 or 35 mm. The compartment roof was 15 mm thick. An entirely new feature of the Semovente M43 da 105/25 were the side skirts protecting the upper portion of the track assembly. It was probably these skirts that gave rise to the nickname the vehicle acquired among the troops — Bassotto, meaning "dachshund", as the skirts somewhat resembled the dog's drooping ears.

The main armament of the new self-propelled gun was the Cannone da 105/25 — sometimes cited with the additional designation Mod. SF. As the designation indicates, this was a 105 mm weapon with a barrel length of 25 calibres. Although formally speaking it was "newly" developed for the self-propelled gun by Ansaldo, it was in fact a modified version of a howitzer produced by rival firm OTO. Unlike the older generations of the Semovente with their 75 mm gun, the 105 mm cannon was mounted on the vehicle's longitudinal centreline and therefore passed through the centre of the front wall of the fighting compartment. The gun mounting allowed a maximum horizontal traverse of 18° to each side and vertical elevation from –10° to +18°. The vehicle's secondary armament was the Breda Modello 1938 machine gun of 8 mm calibre, fed by 24-round clips. The machine gun was not built into the armour but was simply stowed inside the compartment. A total of 48 rounds for the gun and 864 rounds for the machine gun (36 clips) were carried on board.

a Semovente M43 da 105/25 (or Sturmgeschütz M43 mit 105/25 853(i)) and its new owners, source: Worldwarphotos.info with the permission of the site operator, edited

The crew of the self-propelled gun consisted of three men: the driver, the loader who also operated the radio set, and the commander who simultaneously served as gunner. The driver sat at the front left and operated the vehicle using conventional steering brake levers. Directly in front of him was his main vision port in the front wall of the fighting compartment, fitted with a closeable armoured shutter. The port was not filled with any glass — so when open, it was truly open. In combat areas the driver was advised in his own interest to keep it closed and rely on the periscope that opened onto the compartment roof. The gunner and commander sat to the right of the gun and used a periscopic sight that extended through an opening in the compartment roof. The third crew member, serving as loader and radio operator, sat to the left behind the driver. The radio set was mounted at the rear along the left wall of the compartment, which is why the antenna was located on the left side of the roof. The set was of the type Magneti Marelli Radio Fonica 1 per Carro Armato (RF1CA) — a combined transmitter and receiver. According to some sources it had a transmission range of up to 8 km in voice mode and up to 12 km in Morse, which seems rather optimistic. Other sources give figures of only 2 km for voice and 4 km for Morse.

The Italian armistice

As already noted, following the completion of prototype trials the army ordered 130 series vehicles in March 1943. During May and June, however, the order was expanded to 454 — or even 464 — vehicles. The first series vehicle was accepted by the troops on 2 July 1943. By the time the Italian armistice with the Allies was concluded at the beginning of September 1943, probably only 30 examples of the Semovente M43 da 105/25 had been built. With the mention of the Italian armistice we finally arrive at the reason this vehicle features on our website at all. On 10 July 1943 Allied forces landed in the south of Sicily. Over the following weeks they steadily pushed the Italian and German defenders northward, and it was clear to any clear-sighted observer that Sicily would soon fall and the Italian mainland would follow.

Italy's political leadership began to consider whether the time had perhaps come to negotiate with the Allies instead. Any remaining doubt about what lay ahead for Italy was dispelled by the Allied bombing of Rome on 19 July 1943. There was no time to waste. At a session of the government — the Grand Council of Fascism — on 24 and 25 July 1943, Mussolini was removed from the office of Prime Minister and subsequently arrested outright. The newly appointed Prime Minister Pietro Badoglio assured the Germans that Italy remained firmly by their side, but the Germans knew perfectly well what was coming and began preparing for Italy's defection. And defect it did — on 3 September 1943. On the very day that British forces landed on the Italian mainland, the Italians signed an armistice with them. When this was made public — which did not happen until 8 September — the Germans were already prepared and launched the operation codenamed Achse (Axis).

an abandoned wreck of a Sturmgeschütz M43 mit 105/25 853(i), source: Worldwarphotos.info with the permission of the site operator, edited

In German service

Among the main objectives of this operation were the occupation of as large a portion of Italian territory as possible and the disarming of the Italian army. In the course of this disarmament the Germans confiscated from their now former ally an enormous quantity of weapons, including nearly a thousand armoured fighting vehicles — among them 26 examples of the Semovente M43 da 105/25. The Wehrmacht incorporated the captured vehicles into its inventory under the designation Sturmgeschütz M43 mit 105/25 853(i).

In their assessment, the Germans criticised the Italian vehicle's thin armour, inadequate observation means and cramped fighting compartment. Overall, however, they considered it reasonably serviceable, and so decided to continue its production. For as part of Operation Achse they had also acquired the entire Ansaldo-Fossati production plant in Genoa. A further 91 of these self-propelled guns were therefore built before the end of the war, now exclusively for the German army. At the new customer's request, four large teeth were added to the front drive sprockets to prevent the tracks from slipping when under greater tension — for instance when driving on soft ground. Vehicles produced for the German army also most likely did not receive the side skirts protecting the upper portion of the track assembly.

The Germans assigned these self-propelled guns primarily to units fighting directly in Italy — including, for example, the 26th Panzer Division, the 356th Infantry Division and independent assault artillery formations such as Sturmgeschütz Brigade 914 and Sturmgeschütz Brigade 21.

Technical data

ARTICLE
CONTENTS:

A MORE POWERFUL GUN

PROTOTYPE & PRODUCTION

DESIGN DESCRIPTION

THE ITALIAN ARMISTICE

IN GERMAN SERVICE

TECHNICAL DATA