Autocannone da 100/17 su Lancia 3Ro

Kingdom of Italy (1941-1942)
Truck-Mounted Artillery – 16 Converted

The Autocannone da 100/17 su Lancia 3Ro was an Italian truck-mounted artillery vehicle used by the Regio Esercito (English: Royal Army). It was produced in small numbers by converting some heavy duty trucks available in Italian military workshops in North Africa with some obsolete guns. It was used from late 1941, until the final destruction of all the vehicles in 1943. They were meant as support vehicles, but also saw use in the anti-tank role thanks to its shaped charge rounds.

The Italian Army’s Situation in North Africa

On 13th September 1940, one of the most famous and bloody campaigns of the Second World War began. The start of the North African campaign saw Italian troops, commanded by General Rodolfo Graziani, cross the border between Libya, an Italian colony, and British Egypt, a British protectorate.

It was immediately clear to the Italian generals that the Regio Esercito needed reconnaissance armored cars and armed vehicles to support Italian units in the vast deserts of North Africa as soon as possible.

An armed vehicle with great mobility that could reach the battlefront quickly in order to counter enemy attacks and then move to another point of the battlefront to counterattack or for other defensive duties was urgently needed.

Despite the need for such vehicles, development in Italy was very slow. The soldiers in Africa were forced to create such vehicles themselves, in military and civilian workshops. This is where Autocannoni (singular Autocannone) originated from.

The first of a long series of modified autocannoni was the Autocannone da 65/17 su Morris CS8. A significant number of British Morris CS8 light lorries were captured during the first days of war. These were slightly modified and an Italian 65 mm mountain gun was mounted on a 360° rotating support in their cargo bay.

The modifications were done by the Autofficine del 12° Autoraggruppamento AS (English: Workshops of the 12th Motorized Group, AS standing for Africa Settentrionale – North Africa), located in the village of Giovanni Berta, near the city of El Gubba, north-east Libya.

This workshop and the FIAT ones in Tripoli were responsible for the conversion of more trucks into autocannoni. By 1942, autocannoni with howitzers, anti-aircraft autocannons, naval guns, and standard field artillery pieces were produced.

Design

Lancia 3Ro

In the mid 1930s, Vincenzo Lancia, founder of the homonymous car factory, felt the need to develop his own range of trucks in order to respond to the changes in the Italian civilian and military market and also in the European civilian market. This is how Lancia Veicoli Industriali (English: Lancia Industrial Vehicles) was born and started the production of trucks. Due to the lack of knowledge about diesel engines, the Italian company initially purchased patents for German engines.

Reliable Junkers engines were chosen. The first project had a copy of the Junkers 2-cylinder 3,181 cm³ engine. It was produced under license as the Lancia Tipo 89. It gave a power of 64 hp at 1,500 rpm. It was used on the Lancia Ro, of which 5,196 were produced between 1933 and 1939. However, the Lancia Ro had power problems. In order to cope with the increased payload, a new vehicle was introduced in 1935, the Lancia Ro-Ro. Only 301 were built for the civilian market, with a new engine under German license, the Junker 3-cylinder 6 opposed pistons version with a displacement of 4,771 cm³. It was produced under license as Lancia Tipo 90 and gave out 95 hp at 1,500 rpm. This, however, suffered from unreliability.

Vincenzo Lancia then decided to develop his own four-stroke five-cylinder diesel engine in order to decrease the production costs, as the Junkers engines were expensive, and to become more self-reliant.

The prototype of the new 3Ro heavy-duty truck was presented at the 10th Milan Motor Show on 28th October 1937. Officine Viberti of Turin, a leader in the sector and a valuable partner of Lancia, provided the bodywork for the new truck. The prototype had an innovative drop-shaped radiator grille, inspired by that of the Lancia Augusta car. However, this would not be used on the first series of vehicles.

Production started in the same year, replacing the Lancia Ro-Ro on the production line and accompanying the Lancia Ro. Initially, two models were offered: a civilian one with factory number Serie 464 and a military one designated Serie 564. These codes were rarely used even if some sources, for the sake of clarity, define the models as “Lancia 3Ro 464” or “Lancia 3Ro 564”.

The first version of the civilian model retained a fairly rustic bodywork in order to lower the cost of the truck and speed up production. Officine Viberti of Corso Peschiera 249 in Turin was the main provider of bodyworks for the Lancia trucks, which was less than 800 meters from the Lancia plant in the Borgo San Paolo district in Via Monginevro 99.

The first version of the bodywork featured a vertical front grille with an exposed radiator, vertical one-piece hood sides, and single-line vertical air intakes. Customers could privately choose between a short cab with three seats and a long cab with three seats and a berth. The Lancia 3Ro was the third European truck to have the provision for a berth after the FIAT 634N, its main rival on the Italian civilian market, and the French three-axle Renault AFKD produced after 1936. The berth was often made of wood between two sheets of molded steel, although some customers opted for a simpler solution by having the entire berth made of wood.

In 1939, Officine Viberti introduced a new, more modern and elegant bodywork to increase aerodynamic performance, along with a drop-shaped radiator grille, angled windscreen, and more rounded shapes, exactly as would happen with the FIAT 634N.

Given the difficulties encountered by Officine Viberti in keeping pace with the production of Lancia, many customers purchased chassis from Lancia and had the bodywork added privately by Orlandi, Cab, Zagato or even Caproni and Zorzi.

The bodywork for the military model was made by Officine Viberti. This model differed from the civilian version by having 2 horizontal bars, the license plate was on the upper one, to protect the exposed radiator, an inertia starter motor under the radiator grille, doors with fixed windows, acetylene headlights on the sides of the windshield, a wooden floor, and only the rear side of the cargo bay was openable.

Deliveries of the Lancia 3Ro Serie 564 began in 1938, one year after the Serie 464 went into production. A prototype was produced and presented to the Centro Studi della Motorizzazione (English: Motorization Studies Center), the military department which examined new vehicles, in early 1938. After testing, it was accepted into service in the Italian Regio Esercito as the Lancia 3Ro MNP (for Militare; Nafta; Pneumatici – Military, Diesel, Tires) version with standard tires and the Lancia 3Ro NMSP (for Militare; Nafta; SemiPneumatici – Military, Diesel, Solid Tires). Apart from the difference in the type of tires, the vehicles were identical.

According to Lancia sources, a total of 177 Lancia 3Ro Serie 564 were delivered to the Regio Esercito in 1938, 657 in 1939, 2,646 in 1940, 3,162 in 1941(the maximum production rate of 260 3Ro each month was reached this year), 1,643 in 1942, 1,205 in 1943, 51 in 1944 and 1 in 1945. This gave a total of 9,542 heavy-duty trucks. At the same time, 1,307 civilian Serie 464 were built, most of them requisitioned by the Italian Regio Esercito.

After three different bombings of the Lancia plant in Turin, in October 1942, production of the Lancia 3Ro was entrusted to the Lancia Veicoli Industriali plant in Bolzano, in the Trentino Alto Adige region.

In 1939, Lancia Veicoli Industriali proposed the lowered chassis Lancia 3Ro P (P for Passo – Wheelbase, factory code Serie 266) and Lancia 3Ro PL (Passo Lungo, English: Longer Wheelbase) for the civilian market. This was 7.86 m long compared to the 7.30 m of the standard series. These vehicles were to be fitted out as buses by companies such as Garavini, Macchi, Orlandi, or even Officine Viberti.

These versions of the Lancia 3Ro were designed to tow a trailer in order to increase the passenger capacity. The Lancia 3Ro P, with Officine Viberti bodywork, carried 32 passengers plus the driver, with the trailer taking the capacity to over 50 people. In 1940, 78 Lancia 3Ro P chassis rolled off the assembly lines, almost all bodied by Officine Viberti.

In 1942, Lancia Veicoli Industriali proposed a cab-over chassis version of the Lancia 3Ro called P3 (and P3L for the Long Wheelbase version), code Serie 466, of which 142 were produced. In parallel, a conventional forward cabin chassis called Lancia 3Ro P2 (and P2L) was introduced. In total, 611 Lancia 3Ro were produced of the three Passo Lungo variants between 1939 and 1950.

During the war, a gasoline version was developed. This version had a Lancia Tipo 102B engine (B for Benzina – Gasoline). This engine was modified to work with cheaper and more available gasoline and delivered 91 hp. The Lancia Esaro medium truck, a ‘light’ version of the Lancia 3Ro developed in 1941, received an identical engine but with lower power, the Tipo 102B, delivering 80 hp, coupled to the same transmission as the Lancia 3Ro. In 1946, the Lancia Esaro received the same Tipo 102 diesel engine, but giving out only 81 hp.

Like the Lancia Ro, the Lancia 3Ro was available in many special versions for the needs of the army. For transporting quadrupeds, any Lancia 3Ro could be slightly modified with higher cargo bay sides and a two-part loading ramp. The loading bay was divided into multiple boxes by wooden planks to prevent animals from injuring each other.

The Officina Mobile Modello 1938 (English: Mobile Workshop Model 1938) was composed of two vehicles. These were identical to the ones on the Lancia Ro chassis. Apart from the prototype based on a Serie 564 MNSP, it seems that very few were produced.

The civilian version with a water or fuel tank was also adopted for the Serie 546, produced by Officine Viberti, with a capacity of 5,000 liters. It was mainly used in North Africa to transport fuel or water. A trailer with the same capacity produced by Officine Viberti could be attached to it for a total of 10,000 liters.

For the transport of water or fuel, the Serie 546 could be equipped with two removable 2000-liter tanks loaded on the loading bay. This tank did not require any modification to be fitted to the vehicle and was easy to remove, allowing the transport version to be even more versatile.

Employed on all fronts of the Second World War, the Lancia 3Ro was the heavy truck par excellence of the Regio Esercito. It was used to transport troops, animals, or equipment, but was also used as a prime mover for heavy artillery pieces, such as 90 mm cannons and 149 mm howitzers. Officine Viberti or Bartoletti trailers were also designed specifically to be towed by the Lancia and vehicles with similar characteristics for the transport of Italian medium tanks and self-propelled guns.

In North Africa, its good off-road capabilities earned it the nickname ‘Re del Deserto’ (English: King of the Desert). The Allies, particularly the British, reused it in this theater of operations due to its robustness, power, and load capacity. There were trucks captured and reused by the Soviets in the Soviet Union as well.

On the Eastern Front, the Lancia 3Ro was mainly used for the transport of mules and materials of the Alpine divisions of the ARMata Italiana in Russia or ARMIR (English: Italian Army in Russia). In this campaign, it proved to be a reliable vehicle. Even during the harsh Russian winters, the engine was reliable and performed well in very low temperatures that did not allow other Italian and German vehicles to move.

Some Italian veterans claim that the Soviet soldiers usually destroyed all the logistical vehicles that they captured from the Axis troops by rolling over them with tanks during the Don Offensive and the subsequent retreat from the USSR. Eventually, though, they allegedly began to appreciate the qualities of some vehicles, putting the Lancia 3Ro and FIAT 626 that they were able to capture back into service while abandoning the Opel Blitz and FIAT 634N, which they considered performed worse.

After 8th September 1943 and the armistice with the Allies, the Lancia 3Ro were built for the Germans and kept the same bodywork until order 7967/8153. This order, dated 5th April 1944, provided for the delivery of 100 trucks with Einheits cab. This cab, designed by the Germans, was made of plywood planks on a parallelepiped wooden frame. It was very easy to mass produce and adaptable to many Italian trucks, such as the FIAT 628, the SPA TL40, and the Lancia 3Ro.

According to German sources, the Wehrmacht received a total of 772 Lancia 3Ro between January 1944 and February 1945, far more than the production declared by Lancia (52 produced between 1944 and 1945) for the same period. It can be assumed that the German sources were in error, and 772 did not represent the vehicles that were newly delivered by Lancia Veicoli Industriali, but trucks that had previously belonged to the Italian Regio Esercito or private companies and were requisitioned or captured by the Germans. All Lancia 3Ro were assigned to units under the command of the Oberkommando Sud-Est, commanding the Balkans, and Oberkommando Sud-Ouest, commanding Italy.

Some units of the Repubblica Sociale Italiana (English: Italian Social Republic), the Italian Fascist Republic from 1943 to 1945, and some Partisan brigades also used the Lancia 3Ro during the bloody civil war that broke out in northern Italy between 1943 and 1945. In fact, in Turin, in April 1944, the workers allied with the Partisans made an agreement with the factory managers to supply the Partisans with transport vehicles, lubricants, fuel, spare parts, and financial assistance. The number of vehicles delivered is not known. There were no Lancia 3Ro being produced in Bolzano, but spare parts for such vehicles may have been delivered.

During the German occupation, a dozen gas-powered Lancia 3Ro GT (GT for Gassificatore Tedesco – German Gasifier) were also produced.

In late 1945, the Bolzano plant and probably also the Turin ones resumed the production of the Lancia 3Ro, both for the civilian market and for the military.

Initially, very different models grouped under the name Serie 564 NT came off the assembly line. These vehicles were hybrids between the Serie 464 and German production 564. After the war, the warehouses of Bolzano contained dozens of incomplete trucks or raw materials for the military versions. These were diverted for the production of civilian versions. These odd vehicles had military chassis, gasoline engines replacing the diesels, and elongated axle shafts, since the civilian version was wider than the military version.

In 1946, a new model came out: the Lancia 3Ro C (C for Conformità – Conformity) or Serie 564C. It had an electric starter, the width increased to 2,500 mm (2,350 mm for military ones), a new braking system and a ‘full floating’ rear axle instead of the load-bearing axle shafts. It was followed after a year by the Lancia 3Ro C2 (factory code Serie 564C/2) with reinforced tires.

The Lancia 3Ro C versions remained in production until 1948, with mainly Officine Viberti bodywork along with occasionally Orlandi and Caproni. The Military versions were bodied by Officine Viberti. In 1947, the Lancia Esatau 846 or 1 Series came into production. This was equipped with a 122 hp Lancia engine, later increased to 132 hp, and had a top speed of 58 km/h, later increased to 75 km/h.

This vehicle did not receive the attention that was hoped for due to poor power, range, and overall costs. Many truckers preferred the old Lancia 3Ro and Lancia was forced to produce them for another year and a half. The Lancia Esatau 846 and its military version, called Lancia 6Ro, were quickly replaced by other models with a more modern style.

The last 3P and 3PL buses based on the Lancia 3Ro came off the assembly line of the Lancia plants in Bolzano and Turin in 1950. The Lancia 3Ro remained in service with the new Esercito Italiano (English: Italian Army) until 1964 as a medium truck, maintaining high mobility and load capacity, outclassing even modern vehicles produced in the 1950s.

Engine and Suspension

Designed in 1938 on the basis of the previous Lancia Ro and Lancia Ro-Ro, the Lancia 3Ro stood out with its new diesel engine, designed and produced by the Turin company. The Lancia Tipo 102 diesel, 4-stroke, direct ignition, 4 valves, 5-cylinder in-line water cooled engine, with a capacity of 6,875 cm³, delivered 93 hp at 1,860 rpm, leading to a speed on road of 45 km/h. It had a 135 liters tank behind the cab. The tank was connected to a Bosch pump that injected the fuel in the chamber thanks to Bosch injectors.

It had a range of 530 km on-road, with an approximate consumption of 1 liter of fuel each 3.9 km on-road. The off-road range was 450 km with an approximate consumption of 1 liter of fuel each 3.3 km.

Initially, the engine had an inertial starter connected to a crank. The post-war Lancia 3Ro were equipped with electric starters. On some Lancia 3Ro produced before 1946, the inertial starter was replaced by electric ones later.

Semi-elliptical steel leaf springs were used on all four wheels. A trick Soviet soldiers used to stop Axis vehicles during the retreat from the USSR was to dig holes in the roads. With temperatures of below -30 degrees Celsius, the leaf spring suspensions of the trucks would break when they hit such a hole, stopping the vehicle in place. The Lancia 3Ro and a few other models of vehicles did not have this problem, probably due to the quality of the steel with which they were manufactured.

The rear wheel drive was connected to a gearbox with 4 forward and 1 reverse gear and a two-stage reductor, for a total of 8 forward and 2 reverse speeds, with a single dry plate clutch, as on the Lancia Ro and Ro-Ro. It was built under license after a German Maybach model and was located behind the cab for ease of maintenance.

The Lancia 3Ro had expansion shoe type brakes. The brakes were composed of tie rods that acted on the brake shoes and moved two servo conical pulleys. These used force from the transmission when the brake pedal was pressed. This meant that, in the event of a brake system failure whether the vehicle was moving or stationary, the brakes would be locked in place by the brake shoes. This system would be abandoned in favor of a hydraulic system after the war.

The brake system of the trailer was pneumatic, served by a compressor connected to an air tank of the ‘Triplex’ type. After the war, the 3Ro received new arrangements for the towing of 12 tonnes instead of 10 tonnes authorized for the civilian variant.

Aided by the power of the engine, fully loaded trailers could be towed by fully loaded Lancia 3Ros even on steep roads (where other heavy-duty trucks, such as the FIAT 634N, were forced to stop). The pulley brake system worked very well on downhill slopes, braking the enormous mass of the fully loaded truck.

One problem of the Lancia 3Ro was the rear axle, which was composed of two load-bearing axle shafts. This means that, in case the axle shafts broke, the Lancia would get stuck and it was very difficult to move it. Fortunately, this problem was rarely encountered and, after the war, this was replaced with a better performing system. Civilian models produced with this axle were sometimes modified by replacing the axle shafts with stronger ones from other heavy trucks, such as FIAT 666s or Isotta Fraschini D80s.

The electrical system was a 6 volt one in the first 1,611 Lancia 3Ro Serie 564 vehicles, then replaced by a 12-volt system in the following models. It was linked to the Magneti Marelli D90R3 12/1100 dynamo produced by Magneti Marelli of Sesto San Giovanni, which was used to power the two front lights, the license plate and dashboard lighting, the windscreen wipers, and the horn.

Artillery-type forged steel rim wheels could mount various types of tires produced by the Pirelli company of Milan, compatible with the 270 x 20” tires on the 564 MNP and Pirelli Tipo ‘Celerflex’ solid tires with a diameter of 285×88” on the 564 MNSP.

Chassis

Some military trucks were equipped with a winch with a capacity of 9.5 tonnes, with a 31.5-meter long cable. This hydraulic winch was operated by the truck’s engine through a Power Take-Off (PTO) system. When necessary, the driver stopped the vehicle, would shift out of gear on the gearbox, engage the handbrake, and, via a manual override, connected the engine’s flywheel to a second driveshaft that operated the winch’s gearbox, which regulated the speed of the cable.

The 4.8 m long, 2.3 m, and 0.65 m high loading bay was built in wood, with 2.5 cm thick planks, for an internal volume of 66.8 m³. The Lancia 3Ro, weighing 5.61 tonnes, was approved by law to carry 6.39 tonnes of cargo, for a total weight of truck and cargo of 12 tonnes. However, the maximum transportable cargo came to almost 10 tonnes. It could carry 32 fully equipped soldiers on two side benches or almost 50 sitting on the floor, a light reconnaissance tank L6/40 (6.84 tonnes), a Semovente L40 da 47/32 (6.82 tonnes), or even 7 horses.

On the military model, it was not uncommon to see vehicles carrying material for a total of almost 10 tonnes in the loading bay, as well as towing a Rimorchio Unificato Viberti da 15t weighing 3.75 tonnes, with a capacity of 15 tonnes, carrying any tank of the ‘M’ series (M13/40, M14/41 or M15/42) and any self-propelled gun on their chassis for a total weight of truck,trailer, and cargo of almost 30 tonnes.

Main Armament

At the end of World War I, the Kingdom of Italy received or captured or received 1,339 Škoda 10 cm vz. 1914 and 95 Škoda 10 cm vz. 1916 howitzers. These howitzers were joined by 557 cannons and 56 horse-drawn front wagons for the Škoda 10 cm vz. 1916 and 915 guns and 735 horse-drawn front wagons for the Škoda 10 cm vz. 1914 provided by Austria-Hungary as war reparations. These weapons were later incorporated into the Royal Italian Army. In fact, the Italian Army suffered from a lack of light howitzers to accompany the Cannoni da 75/27 Mod. 1906 and the 75/27 Mod. 1911 in the field artillery regiments.

The Cannone da 105/14 Modello 1917 howitzer, which was produced by Ansaldo under license, arrived too late to take part in the conflict. Moreover, its range was inferior to the Škoda howitzers and was quickly decommissioned from active service and stored.

After World War I, other nations adopted these Škoda howitzers, entering service with the Austrian, Czechoslovakian, German, Hungarian, Polish, Romanian, Turkish, and Yugoslav armies. In Italian service, the Obice Škoda da 100/17 Modello 1914 was renamed Škoda 10 cm vz. 1914 and the Obice Škoda da 100/17 Modello 1916 as Škoda 10 cm vz. 1916.

The Obice da 100/17 Mod. 14 was towed by a horse-drawn front wagon. It weighed 1,417 kg in battery position. Designed for use in the mountains, it could be divided into 3 parts, allowing it to be transported on narrow paths on the back of mules.

The Obice da 100/17 Mod. 16 was intended exclusively for mountain use and was lighter than the previous model, at 1,235 kg. The new model retained the ballistic performance of the Mod. 1914. The main differences were the reduction in size, the reduction of the wheel diameter to facilitate movement on narrow paths, the increase of the maximum elevation, and the adoption of a new two-part flat shield.

The main weaknesses of the Škoda 10 cm howitzer was its range of 8,180 m and a low horizontal traverse of only 5° due to the single central trail. After 1918, the Royal Italian Army captured and received a small stock of ammunition. Therefore, the Italian industry had to start almost the production of the 100 mm ammunition.

In 1932, a new projectile was produced. It had 2.3 kg of TNT equivalent explosive filler and better ballistics, giving it an increased range by about 500 m, bringing it to almost 9 km.

As with most artillery pieces after the First World War, the 100 mm Mod. 14 and Mod. 16 howitzers had problems with mechanized transport. In fact, since they were designed to be towed by 6 horses at very low speed, they had no suspension, which caused problems when being towed by trucks and caused damage to the barrel due to vibrations.

In order to solve this problem, in the 1920s, two different solutions were adopted. The first was a trolley with rubber wheels positioned under the howitzer, which was then hooked to the truck. The second option was having the original 12-spoke wooden wheels replaced by metal wheels with solid rubber tires. These modifications received the acronym TM or Traino Meccanizato (English: Mechanized Towing).

The Obice da 100/17 Mod. 14 had a depression of -8° and an elevation of +48°, while the traverse was 5°21′. The Obice da 100/17 Mod. 16 had a depression of -8° and an elevation of +70°, while the traverse was 5°5′. The maximum rate of fire was 10 rounds per minute, but in order to lessen the stress on the mechanical parts and to keep the barrel from overheating, the usual rate of fire on the autocannoni was 5-6 rounds per minute. The muzzle velocity was 430 m/s with High-Explosive rounds.

On 1st October 1939, the Italian Regio Esercito had 1,325 Obici da 100/17 Mod. 14, which were horse-drawn or used in fixed positions, 199 Obici da 100/17 Mod. 14 TM, and 181 Mod. 16 howitzers.

The weapon thus constituted, along with the 75/27 gun, the backbone of the Italian divisional artillery regiments. In North Africa, in October 1941, there were 137 100 mm TM howitzers, which were reduced to 56 by February 1943. In this theater of operations, Škoda howitzers had problems on off-road transport because of the soft sand, in which they sank. They were also criticized for their insufficient range.

In April 1942, the Regio Esercito could still count on 173 Obici da 100/17 Mod. 16, 194 Mod. 14TM, and 1,583 Obici da 100/17 Mod. 14 horse-drawn howitzers. Many of the losses incurred were offset by the supply of guns captured from the Polish by the Germans and pieces captured from Yugoslavia.

In June 1943, there were still 37 divisional artillery groups equipped with Škoda howitzers Mod. 14, of which 11 were motorized, and 10 groups equipped with the Mod. 16. As such, the 100 mm remained the standard light howitzer of the Italian Regio Esercito throughout the war.

After the armistice of 8th September 1943, the Germans captured several hundred of these howitzers and reused them under the name of 10 cm FH 315(i). After the war, the surviving howitzers received a ring mount identical to that of the British 25-pounder howitzer, giving it 360° traverse. The barrels were rebored from 100 mm to 105 mm and the breeches replaced. The resulting howitzers were capable of firing standard NATO ammunition and remained in service until the mid-1980s for training purposes.

Ammunition

The Obice da 100/17 Mod. 14 and Mod. 16 could fire different types of rounds with the 100 x 132 mmR cartridge.

Granata Dirompente da 100High-Explosive (HE)12.73

Obice da 100/17 ammunition
Name	Type	Weight (kg)
Granata Perforante da 100	Armor Percing (AP)	//
Granata a Doppio Effetto da 100	High-Explosive (HE)	12.93
Granata Shrapnel	Shrapnel	11.45
Granata da 100 Modello 1932	High-Explosive (HE)	13.80
Granata a Doppio Effetto da 100 Modello 1932	High-Explosive (HE)	13.33
Granata a Doppio Effetto da 100 Modello 1936	High-Explosive (HE)	13
Effetto Pronto	High-Explosive Anti-Tank (HEAT)	//
Effetto Pronto Speciale	High-Explosive Anti-Tank (HEAT)	//
Granata Incendiaria da 100	Incendiary	//
Granata Fumogena da 100	Smoke	//
Granata Lacrimogena da 100	Tear Gas	//

Despite the short-range and low muzzle velocity of the projectile, the 10 cm howitzer was often used in the anti-tank role. The hollow-charge armor-piercing Effetto Pronto projectiles were designed for this weapon and were delivered in very small numbers to the units in mid-1942. This new projectile was tested in Germany in November 1942 against captured Soviet tanks and demonstrated its capabilities against T-34-76 medium tanks and KV-1 heavy tanks. Italian 100 mm EP ammunition proved at least as effective as German 105 mm HL ammunition, suggesting that it could penetrate a 100 mm ballistic steel plate angled at 90°. In May 1943 a more powerful projectile, dubbed the Effetto Pronto Speciale, was adopted.

The Autocannone da 100/17 su Lancia 3Ro could transport 100 rounds on board. The ammunition was carried in two 50-rounds wooden racks in the cargo bay, right behind the cabin. Other projectiles were transported on truck ammunition carriers assigned to each battery.

Secondary Armament

The secondary armament on the Autocannone was a single Breda Modello 1938 medium machine gun. This gas-operated machine gun was developed by Società Italiana Ernesto Breda per Costruzioni Meccaniche in 1938 and accepted into service in the same year.

This was the vehicle version of the powerful machine gun adopted as the company or battalion support heavy machine gun by the Regio Esercito, the Breda Modello 1937. The Mod. 37 was the heaviest rifle-caliber machine gun of the Second World War, with a weight of 19.4 kg, while the Mod. 38 was smaller, with a weight of 15.4 kg, thanks to the shortened barrel of 575 mm compared to the 740 mm long-barrel of the Mod. 37. The machine guns were probably taken from some knocked out Italian medium tanks, like some other parts of the autocannoni.

The machine gun had a theoretical rate of fire of 600 rounds per minute, over 100 rounds per minute more than the Mod. 37. Due to the 24-round top-mounted curved-magazine, the practical rate of fire dropped to around 350 rounds per minute.

The machine gun fired 8 x 59 mm RB cartridges developed by Breda exclusively for machine guns. The 8 mm Breda had a muzzle velocity between 790 m/s and 900 m/s, depending on the round type. The armor piercing ones penetrated 11 mm of non-ballistic steel angled to 90° at 100 meters. Unfortunately, where the ammunition was stowed and the precise number of magazines carried on board the Autocannone is unknown. Some vehicles had anti-aircraft support mounted on the cabin’s left.

Crew

The crew was composed of 6 soldiers: commander, driver, gunner, two loaders, and another gun operator. The driver sat on the right side of the open-topped cab while the vehicle’s commander/gun commander sat on the left side. Between the two, there was enough space for an additional gun crew member. The gunner and two loaders were placed on the cargo bay.

When firing the gun, the driver helped to reload the gun or operated the anti-aircraft machine gun. The drivers of the supply trucks assigned to the batteries also helped to fire the gun to speed up the gun’s rate of fire.

For close defense, crews stored their personal weapons in the spacious Lancia 3Ro’s cargo bay. Usually, the crews were only armed with Carcano Modello 1891 in carbine or rifle versions.

Modifications

The Autofficine del 12° Autoraggruppamento Africa Settentrionale modified Lancia 3Ro heavy duty trucks, cutting out the cabin roof and sides under the windshield level, giving 360° of traverse for the howitzer. On the cargo bay, two box-shaped wooden ammunition racks and a bench for the gun loaders were added.

Some 20 liters can supports were placed under the cargo bay. From the photographic sources, these held 6 cans and were welded to the frame of the truck on the left side, in front of the rear wheel. However, since this was a mostly improvised vehicle, the supports changed sometimes. Other photos show vehicles with a 3 can support. With the six 20 liters cans filled with fuel, the vehicle could have a theoretical range of 1,000 km on-road and 850 km off-road. With 3 cans, it could have a theoretical range of 750 km on-road and 650 km off-road. Apart from these modifications the vehicle was left unchanged.

A turret rotation ring, taken from destroyed medium tanks of the ‘M’ series, such as the M13/40, was placed on the cargo bay. The ring held a platform on which the Obice da 100/17 Mod. 14 or Mod. 16 howitzer mount was welded.

The howitzer carriage was modified, removing the wheels, the spade, shortening the trail, and removing the armored shield. This ingenious system allowed for 360° of traverse. At the front, over an arc of 33° to the right and 33° to the left, the howitzer could only fire at a minimum elevation of +5° due to the cabin and ammunition boxes. Over the remaining 294°, the gun could fire with a depression of -8°.

The vehicle did not have jacks to lift it off the ground, as on other autocannoni. The recoil of the gun was quite low and did not cause any damage to the chassis.

However, with each shot, the vehicle moved some centimeters even with the handbrake on, a problem that was solved by putting wooden wedges under the wheels. This forced the gunner to re-aim the howitzer after each shot. The necessity of re-aim the main gun after each shot slowed down the rate of fire while the presence of the wedges forced the crew to remove them when the vehicle needed to be transferred in another place did not permit them to quickly relocate to avoid British counter-batteries fire.

Italian writer Nico Sgarlato, in his book ‘I Corazzati di Circostanza Italiani’, claims that around 20 other autocannoni equipped with 100 mm howitzers on Lancia 3Ro hulls were produced in 1942, but there is no evidence for this.

Operational Use

The first vehicle was ready in late September 1941. The tests began on 29th September 1941 and included six days of driving on asphalt, dirt, and off-road, with an average length of 170 km. After each mobility test, firing tests were carried out to assess whether the stress of the howitzer’s recoil caused damage to the vehicle’s chassis.

A total of 1,019 km were covered by each vehicle and 1,782 rounds of 100 mm were fired. The maximum speed reached was 40 km/h on asphalt and 30 km/h on dirt roads. Off-road, the maximum speed was between 15 and 30 km/h. On soft sand, the bulk of the vehicle made it sink, slowing it down, but on stony terrain the great mobility of the Lancia 3Ro allowed it to overcome most obstacles.

Fire exercises were carried out with direct and indirect fire at short, medium and long distances. Even when the weapon was aimed to the sides, no balance problems were encountered.

By the fall of 1941, the first battery composed of the four autocannoni, along with ammunition carriers and other logistic vehicles based on captured Morris 30-CWT medium trucks and Italian Lancia 3Ro heavy trucks, was formed. This was the 14ª Batteria Autonoma (English: 14th Autonomous Battery), one of the 16 batteries equipped with autocannoni. On 23rd November 1941, during Operation Crusader, the unit clashed with British tank formations, inflicting heavy losses on the enemy. Unfortunately, nothing is known about its position on the battlefield and if the battery was assigned to an Italian or a German unit.

On 1st December, the 14ª Batteria Autonoma attacked a British supply depot in the desert, probably with the support of units of the 132ª Divisione corazzata ‘Ariete’ (English: 132th Armored Division) units. However, during the attack, German Junker Ju. 87 “Stuka” ground attack aircraft attacked the battery, mistaking it for British trucks.

Some sources claim that all the four autocannoni with 100 mm howitzers and some autocannoni da 65/17 were destroyed, while others claim that one autocannone da 100/17 survived and was destroyed some time after during Crusader Operation during a fight against British tanks. A total of 6 soldiers and a NCO were killed in the airstrike.

Three more batteries, equipped with 4 Autocannoni da 100/17 su Lancia 3Ros each, were created in 1942. They were part of the XVII Gruppo (English: 17th Group) that was assigned to the Raggruppamento Celere Africa Settentrionale (English: North Africa Fast Grouping).

The Raggruppamento Celere Africa Settentrionale was composed of two Gruppi Celeri (English: Fast Groups), each containing an armored car squadron with 48 AB40 and AB41 armored cars, one Gruppo Batterie da 65/17 Autoportate (English: Truck-mounted 65/17 Battery Group), one Gruppo Batterie da 75/27 Mod. 11 Autoportate, one Gruppo Batterie da 100/17 Autoportate, and one Batteria Antiaerea da 20/65 (English: 20 mm Anti-Aircraft Battery). These units were supported by 2 infantry battalions and a logistic unit.

In January 1943, the XVII Gruppo was passed to the 136º Reggimento artiglieria (English: 136th Artillery Regiment) of the 136ª Divisione Corazzata ‘Giovani Fascisti’ (English: 136th Armored Division).

The ‘Giovani Fascisti’ artillery regiment was composed only of autocannoni batteries: the XIV Gruppo and XV Gruppo were equipped with Autocannoni da 65/17 su Morris CS8, the XVI Gruppo equipped with Autocannoni da 75/27 su FIAT-SPA TL37, the XVII Gruppo with Autocannoni da 100/17 su Lancia 3Ro and, finally, the 88ª Batteria Artiglieria Contraerea (English: 88th Anti-Aircraft Artillery Battery) was equipped with Cannoni-Mitragliere da 20/65 Modello 1935 loaded on Ford and Chevrolet trucks.

Unfortunately, sources very rarely mention the use of the autocannoni armed with the 100 mm howitzers. It is plausible that, due to the small number of Autocannoni da 100/17 su Lancia 3Ro produced, most of them were lost during 1942, during the desert battles against British troops.

It is, therefore, logical to assume that, when the XVII Gruppo was assigned to the 136º Reggimento artiglieria, it had half, or perhaps even less of the initial vehicles. The XVII Gruppo probably had other autocannoni or even field artillery pieces in its ranks to replace losses.

Conclusion

The Autocannoni da 100/17 were have been effective in the African Campaign, where their timely intervention could turn the fortunes of some battles. However, few were built and there is little information about their use. They were also unarmored and vulnerable to enemy small arms fire or air attacks and lacked protection for the crew, who were vulnerable to shrapnel and small bullets.

Autocannone da 100/17 su Lancia specifications
Dimensions (L-W-H)	7.25 x 2.35 x 2.3 m
Total weight, battle-ready	6.5 tonnes
Crew	6 (commander, driver, gunner, and 3 loaders)
Propulsion	Lancia Tipo 102 diesel, 5-cylinder, 6,875 cm³, 93 hp at 1,860 rpm with a 135 liter tank
Speed	40 km/h
Range	530 km
Armament	One Obice Škoda da 100/17 Modello 1914 or Modello 1916 and a 8 mm Breda Modello 1938 medium machine gun
Armor	//
Total production	16 converted

Sources

I corazzati di circostanza italiani – Nico Sgarlato
Italian truck-mounted artillery in action – Ralph Riccio e Nicola Pignato
Gli Autoveicoli tattici e logistici del Regio Esercito Italiano fino al 1943, Tomo II – Nicola Pignato and Filippo Cappellano
Gli Autoveicoli del Regio Esercito nella Seconda Guerra Mondiale – Nicola Pignato and Filippo Cappellano
Ruote in divisa, un Secolo di Veicoli Militari Italiani – Brizio Pignacca