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WW2 French AT Weapons

Canon de 25mm Semi-Automatique Modèle 1934 Modifié 39

ww2 French Tanks France (1938-1940)
Anti-Tank Gun – Unknown Number Built

The French Army started to experiment with armor-piercing weapons as early as the Great War. During the German offensive of 1914, a vastly overestimated armored car scare led to the French army mobilizing naval 47 mm guns for anti-armor work, notably creating the Autocanon de 47mm Renault. The entrenchment of both sides as 1914 morphed into 1915 put an end to this armored car scare. Later in the war, as tanks became an actively used weapon, countering them became a source of worry again. The vehicles were first employed by France’s ally, Britain, and then by the French themselves, before the Germans would be able to produce and employ their own. But the possibility remained there, and the German Army would also widely use captured British tanks. As such, a number of options were studied as early as 1917 or 1918. This included some infantry support guns which were hoped to also fulfil an anti-armor role, such as the ill-fated American-made 37 mm Bethlehem Steel gun, or the mounting of the ubiquitous 75 mm modèle 1897 gun on a wooden platform which guaranteed high lateral traverse. In the last weeks of the conflict, the French tested what appeared to be a more mature and potent solution to the problem of enemy tank, the 17 mm Filloux, a high-velocity (1,000 m/s) anti-tank gun firing a small caliber, 17×209 mm semi-rimmed cartridge, mounted on the carriage of the very common 37 mm TR modèle 1916 infantry support gun.

The conclusion of the Great War would result in the threat of enemy armored fighting vehicles being vastly less urgent, and likely due to less interest from a scaling-down military, the 17 mm Filloux would not go anywhere. Nonetheless, studies on the matter of anti-tank guns continued in France. While a curious Delaunay-Belleville DB20 20 mm weapon, seemingly sometimes called an “anti-tank machine gun”, was offered in a similar timeframe or soon after the Filloux, it was not adopted either.

In 1921, France launched a program that envisioned both a 10 to 15 mm dual-purpose anti-tank and anti-aircraft machine gun, as well as a dedicated high-velocity anti-tank gun of a caliber smaller than 37 mm. This program would fail to result in the adoption of an anti-tank gun. The machine gun requirement would result in a 13.5 mm MAC dual-purpose prototype and later the 13.2 mm Hotchkiss, which was used strictly in an anti-aircraft role. Meanwhile, in 1927, the state workshop of APX (Atelier de Constructions de Puteaux – Puteaux construction workshop) offered a 20 mm anti-tank gun. The caliber was found to be too small to result in sufficient armor-piercing capacities. New specifications requesting a 25 mm semi-automatic gun were issued in 1928. Prototypes from both APX and Hotchkiss would be pursued. The Hotchkiss design would finally be adopted in 1934. One can lament how the French Army had the conceptual requirements for an anti-tank gun as early as 1921, but would only be able to start issuing one in the middle of the 1930s.

The 25 mm Hotchkiss

The 25 mm anti-tank gun the French army adopted in 1934 was a potent gun. While small in diameter, its long, 72 caliber barrel granted a high 950 m/s muzzle velocity to its 25×193.5 mm rimmed tungsten core projectiles. Able to penetrate a 40 mm plate at a perpendicular angle and a range of 400 m, or a 32 mm plate at an angle of 35° and a range of 200 m, the gun would have had little issue dealing with most tanks used in the mid-1930s.

Abandoned Hotchkiss anti-tank guns still attached to their Renault UK Trailers during the Battle of France. Source: pinterest

Nonetheless, some aspects of the Hotchkiss gun, especially those concerning the shield and carriage, betrayed its 1920s conception. Despite its small caliber, the 25 mm SA 34 was still a fairly heavy piece, at 480 kg in battery. This would prove an issue when manoeuvring the gun around. During traction, it also meant that towing the gun with a single horse would be quite slow and tiring for the animal. On the topic of traction, the gun also suffered as it had no suspension. As a result, it could only be towed at slow to moderate speeds. When adopted, the French Army regulations stated the gun could be towed only at a maximum of 15 km/h on a good road, 10 km/h on an average road, and 6 km/h on cross-country. After a little under 2,000 guns had been produced, modifications allowed the traction speed to rise to 35, 20, and 10 km/h respectively, which was better, but still not particularly fast. In other words, while it offered a modern and potent weapon in terms of ballistics, the carriage of the 25 mm Hotchkiss could still be improved in order to make the operation of the gun easier.

APX Works on Hotchkiss’ Gun

Upon adoption of Hotchkiss’ gun, the issues of weight and traction were not entirely out of the French Army’s consideration. As early as the adoption of the gun, APX’s engineers were asked to try and come up with a lightened design which would be easier to move around.

French troops by the side of a camouflaged APX 25 mm SA-L 37 anti-tank gun, 1940. Source: supper-hobby.com

APX, having taken part in the competition that resulted in the adoption of the Hotchkiss gun with their own prototype, quickly came up with a modified version of the 25 mm anti-tank gun. The APX-modified Hotchkiss design offered a first prototype in 1936, though it differed significantly from the definitive model adopted in 1937. Compared to the original gun, the APX SA-L 1937 managed to massively lower the weight from 480 to 310 kg while keeping identical armor-piercing performances. The adoption of a new, simpler shield design contributed to the weight loss. However, the main reduction was with the use of a 193 kg carriage instead of the 386 kg on the Hotchkiss 25 mm SA 34. As a result, the gun was more fragile, and was strictly prohibited from motorized traction. Strict orders were given for it to only be transported under by horses, at maximum speeds of 15 km/h on a good road, and 10 km/h cross-country. Nonetheless, the weight losses were still significant, and the APX-modified gun was adopted as the 25 mm SA-L 37 (25 mm Semi-Automatique Allégé modèle 1937 – Eng: 25mm, semi-automatic, lightened, 1937 pattern) and entered production alongside the Hotchkiss gun.

Putting the Same Men at Work, Under a New Employer

While the French Army put APX’s engineers to work on a lightened version of the Hotchkiss gun, this did not mean that the original Hotchkiss designers were not put to work on improving their design either.

In 1936, the new left-wing government of France, known as the Popular Front, led massive nationalization of the French armament industry, with the desire to put this critical sector under the control of the state rather than private companies. In this context, the armament factories of Hotchkiss, in Levallois-Perret, were nationalized in August 1936.

The engineers at Levallois likely started to work on an improved version of their anti-tank gun at an earlier point. Unlike APX, they opted for a different solution on how to improve the 25 mm anti-tank gun. While still aiming to lighten the gun to an extent, another equally important goal was to enable high-speed traction on the new design. The first clear trace of an improved 25 mm gun from Levallois is dated from February 24th 1937, when the factory confirmed the improved anti-tank gun it was working on would be finished soon. In practice, however, it would be another year and a half before a prototype of the improved 25 mm anti-tank gun from Levallois would be put to trial. The improved gun would begin experimentation on July 12th 1938.

Design of the Levallois 25 mm Lightened Anti-Tank Gun

The prototype appears to have been, by this point, known as the Canon de 25 SA allégé (Eng: Lightened 25 SA gun, SA standing for Semi-Automatic) or Canon de 25 mm SA Hotchkiss adapté à la traction rapide (Eng: Hotchkiss 25 mm SA gun modified for rapid traction).

The 25 mm Levallois prototype in its original configuration, still sporting a muzzle brake. The wavy top of the gun shield was intended to break the silhouette of the anti-tank gun and make it more difficult to identify as a man-made object when camouflaged and at range. Source: GBM 98

Some very significant modifications had to be undertaken around the carriage in order both to lighten the gun and allow high-speed traction. Likely, the most significant was the addition of a suspension. The gun used wheels fairly similar to those used on the APX SA-L 37. These were aluminum wheels with 14 ribs and holes separating each of these in order to lose weight, with pneumatic 67 cm in diameter tires. These wheels were mounted on a deformable axle mounted on springs. The carriage retained a split-trail, which would automatically lock the suspension when deployed.

A number of additional changes were made to the gun in order to lighten it. Most of these involved using thinner construction for elements, such as the split-trail, as well as lighter steel. This lighter construction material was notably used in the elevation and rotation wheels as well as sight holder. The complex multiple-piece shield of the 25 mm SA 34 was ditched and replaced by a much simpler and thinner one-plate shield, with an opening to the top right of the barrel through which the sight would be placed. The thinner thickness of the shield was compensated by it being angled further back, with an incidence of 30° in comparison to 15° on the SA 34. The shield offered less protection to the gun’s crew in comparison to the 25 mm SA 34, but this was deemed an acceptable loss.

There were also some modifications unrelated to the weight of the gun itself. The traverse and elevation mechanisms of the gun were now locked when in travel mode. However, the gun was also modified so that it could be aimed, traversed and elevated without deploying the split-trail if need be. The four contact points of the gun with the ground, aka the end of the split-trail and the wheels, were revised in order to ensure greater stability. The modified gun also removed the pistol grip featuring a trigger present on the original gun. Instead, the trigger-lever was found under the carriage. A firing mechanism was also added to the traverse wheel.

Front view of a 25 mm SA 34 (left) and the Levallois lightened 25 mm prototype (right). The much simpler gun shield is obvious. By this point, the Levallois gun has been revised and now sports a muzzle brake. Source: GBM 98

Dimensions wise, the gun was fairly similar to the 25 mm SA 34, with slight differences. It had a width of 1.13 m, a total length of 3.46 m in travel mode, and a height of 1.08 m. The lateral traverse was identical to the 25 mm SA 34, with 30° to either side, giving a forward 60º field of fire. The elevation and depression were -5° to +15°. In terms of weight, the gun was 110 kg lighter in battery, at 370 kg. The gun itself was barely lighter, at 89 kg in comparison to the SA 34’s 90 kg. The weight reduction had largely been carried out with the carriage, which went from 386 to 281 kg, and the shield, which went from 75 to 38 kg. There were little to no modifications in the design of the gun itself. It retained the same 25×193.5 mmR cartridges, the same L.711 sight, and a similar semi-automatic breech granting a theoretical rate of fire of around 30 rounds per minute, and a more practical one of 15 to 20.

Trials and Modifications

Trials began in July 1938 at the Etablissement d’expériences techniques de Versailles or EETVS (Eng: Versailles Technical Experience Establishment). These trials included the firing of 500 projectiles, and being towed by motor vehicles for 500 km in varied terrain and then 3,000 km on roads.

Mobility-wise, the gun performed very well. The said distances were crossed at an average speed of 55 km/h, and sometimes peaking at up to 85 km/h. The suspension was found to perform very well and make the gun easy to move around across all types of terrain and by all types of vehicles, including Renault UE tracked tractors, lorries, horses, and likely half-tracks. The only issue found was light damage on one of the wheels, which was not particularly out of the ordinary after such distances were crossed. The mobility of the gun, when moved around by its crew in the field, was also tested. The gun was subjected to comparative trials against the 25 mm SA 34. Both guns were carried around by a five-man team through 200 m of varied, cross-country terrain. The team moving the Levallois lightened gun around were found to cross this distance in 3.25 minutes and still be in good shape at the end of it, whereas the team moving the 25 mm SA 34 around needed 6.05 minutes to cross the same distance and were exhausted by the end. These good performances would result in it being rated for 70 km/h on a good road, 40 km/h on an average road, and 15 km/h cross-country. Seeing as the gun was towed around at 85 km/h without issue during trials, it is likely these regulations were conservative to an extent.

While, mobility-wise, the gun was excellent, there were some issues when firing. The lighter construction of the gun led to an increase in recoil. While the movement of the gun backward was the same as on the 25 mm SA 34, at 240 mm, it was felt more strongly. This was found to be a particularly negative issue during the first few shots taken in a new position, when the gun was still ‘anchoring’ itself in the ground. At these moments, a gunner would have to remove their eyes from the sight before firing, taking the risk of light injury around the eye if this was not done. This was obviously not judged as acceptable by the trials commission, which sent the gun back to Levallois for a few days so modifications could be undertaken during the trials. The solution by Levallois’s engineer was to remove the flash hider, similar to the one found on the 25 mm SA 34, and replace it with a circular muzzle brake. This proved sufficient to reduce the recoiling length to 200 mm and solve any issue with the gun potentially injuring its operators during recoil.

The 25 mm Levallois prototype after it received modifications, notably the installation of a muzzle brake. Source: GBM n°98

There were still some minor issues with the gun. The addition of a muzzle brake was found to result in some projections of dust, small rocks, or mud towards the crew, particularly when the barrel was particularly close to the ground, as could be the case in fortifications. The trigger configuration was also found to be inferior to the 25 mm SA 34, of which the pistol grip was dearly missed. However, it was also found to have a number of advantages. Performance-wise, it was very similar to the 25 mm SA 34, but putting the gun in battery, or out of battery, was a much easier and less effort-intensive task for the crew. When maneuvering the gun around, the weight carried by each crewmember was found to be of 17 kg, while it would have been 33 on the 25 mm SA 34. These advantages were judged sufficient by the trials commission tasked with testing the gun to deem it “un bon matériel de guerre” (Eng: A good wartime piece of equipment). On January 10th 1939, the French Direction of Infantry formally adopted the gun as the Canon de 25 mm SA modèle 1934 M.39 (Eng: 25 mm SA gun 1934 pattern M.39, with M.39 standing for modifié 1939 – modified 1939)

Elements similar to the 25 mm SA 34

The exact anti-armor performances of the 25 mm SA 34 M.39 are not known. However, we know they were close enough to the 25 mm SA 34 to the point where the need to report them was not felt. Trials of the Balle P anti-armor projectile on the 25 mm SA 34 indicated a penetration of 40 mm on a vertical steel plate at 500 m, and 32 mm on a plate at an angle of 35° and a range of 200 m. German tests performed with captured guns give a more extensive range of values. Against a vertical plate, the shell penetrated 47, 40, and 30 mm of armor at 100, 500, and 1,000 m, respectively. At 30°, the penetration values were 35, 30, and 20 mm. Finally, at 45º, they were 18, 16, and 15 mm.

The view offered by the APX L.711 sights. Extract from the Notice sur le canon semi-automatique “Hotchkiss” de 25mm du 2 Janvier 1935, in its 1937 edition, by the Ecole Militaire & d’Application de la Cavalerie et du Train
Figure showing the various types of projectile, as well as the standard Balle P and its tungsten core. Extract from the Notice d’instruction de l’école des chars de combat, 1937, via the French National Library/Gallica

The sights used on the 25 mm SA 34 and on the M.39 were the lunette L.711 APX modèle 1936, which offered a 4x magnification, 11° field of vision, and markings for firing at up to 3,500 m. It was not fixed to the carriage, and was carried in a separate case. The opening to insert the sight into was found on the top right of the barrel.

The crew of the 25 mm SA 34 and of the M.39 would comprise six: a commander, a gunner placed to the left of the gun, a loader placed on the right, and three additional gun crewmembers. If the gunner was knocked out, their replacement was the loader, and if the loader was knocked out, they were replaced by the second spare crewmember, who otherwise cleaned and handed over the 25 mm cartridges from the crates. In practice, the gun could remain reasonably effective with two crewmembers, and still be operated, albeit with a much lower rate of fire, by a single crewmember.

Production Schedule

The modified gun was adopted in January 1939 and, in long-term planning, was intended to replace the 25 mm SA 34 on the production line, and eventually in the army. However, switching the production lines to the new gun would take some time. – By Spring 1940, production of the 25 mm SA 34 was still in full swing and even increasing.

It does appear that a few pre-production 25 mm SA 34 M.39 pieces may have been completed. According to one report, two guns were in service, likely for experimental purposes, within the 1ère Division d’Infanterie Motorisée (1ère DIM) (Eng: 1st Motorized Infantry Division) on April 1st, 1940. No view of these guns has ever emerged, and as such, their existence remains hypothetical and should be treated as such. The gun was intended to be distributed in priority to motorized unit, such as the BCPs (Bataillon de Chasseur Portés – Eng: Motorized Chasseurs Battalions), CDACs (Compagnie Divisionnaire Antichar – Eng: Divisional Anti-Tank Company) and motorized infantry regiments. In the meantime, the prototype was still being used experimentally, with the last known firing trials being held as late as May 7th, 1940.

Deliveries of the first production examples were to start in June 1940, with the first 50 examples scheduled to be delivered during this month. What eventually befell these is unknown. The facilities of Levallois would have been taken, alongside Paris, on June 14th. In previous decades, there were some rumors that up to 400 may have been completed, but more recent research has disproven such claims. Currently, uncertainty exists as if some may have even been fully completed. If so, they likely saw little to no operational use, or may even have been captured intact before delivery by German troops. If they indeed existed, the two pre-production guns part of the 1ère DIM may very well have fought, seeing as the division was engaged, and later annihilated, in the French manoeuver to safeguard Belgium and the Netherlands, Plan Dyle-Breda, ending in the encirclement of much of the best elements of the French Army, the British Expeditionary Force, and the Belgian Army around Dunkerque.

Conclusion – The Last Evolution of the French 25 mm

The Canon de 25 mm SA modèle 1934 M.39 was the most advanced model of the French 25 mm gun. When comparing it to the standard gun adopted in 1934, its operation would generally be easier due to a suspension and lighter weight which granted the gun a much better mobility, either when being towed behind a horse or vehicle or when being moved around by its crew in the field. Performance-wise, the gun was identical to the standard 25 mm, which proved adequate during the 1940 campaign.

One can still raise questions on how long the new 25 mm would have remained a useful piece of equipment. The issue with such a low-caliber is that, as the war went on, creating more powerful ammunition would likely have proven to be a struggle. As a matter of fact, as early as 1940, studies for Brandt sub-caliber ammunition which would highly improve armor-piercing performances were underway for a number of calibers. These included the French 37 mm or 75 mm, as well as 155 and 203 mm calibers for the navy, but, crucially, none appears to have been considered for the 25 mm. As such, it is likely the gun would slowly fall into obsolescence in the coming years, even if it was actually produced. While some small-caliber armor-piercing weapons, such as Soviet 14.5 mm anti-tank rifles, proved to remain useful for the duration of the war, albeit typically not as much as in the its early phases, these were typically man-portable anti-tank rifles which would be far easier to move around to target the sides and other weak areas of a tank’s armor coverage than a field gun, even a particularly light and mobile one.

Canon de 25mm SA modèle 1934 M.39 in its late configuration, mounting a muzzle brake, illustrated by Ardhya ‘Vesp’ Anargha, funded by our Patreon campaign.
Canon de 25mm SA modèle 1934 M.39 in its early configuration, illustrated by Ardhya ‘Vesp’ Anargha, funded by our Patreon campaign.
Weight (Deployed) 370 kg
Length (With Carriage) 3.46 m
Height 1.08 m
Width 1.13 m
Maximum towing speed 70 km/h (good road)
40 km/h (average road)
15 km/h (cross-country)
Caliber 25 x 193.5 mm
Traverse 60°
Elevation -5° to +15°
Rate of fire 8 – 20 rpm, up to 25 rpm with a well-trained crew
Sight Range 3,500 m
Effective range 800 m

Sources

GBM n°97, Juillet-Août-Septembre 2011, “Les canons semi-automatiques antichars de 25 mm Première Partie: Le canon de 25 mm SA modèle 1934”, Eric Denis et François Vauvillier, pp 86-95

GBM n°98, Octobre-Novembre-Décembre 2011, “Les canons semi-automatiques antichars de 25 mm Deuxième Partie: Les dérivés du 25 mm SA modèle 1934”, Eric Denis, pp 28-31

Notice sur le canon semi-automatique “Hotchkiss” de 25mm du 2 Janvier 1935, in its 1937 edition, by the Ecole Militaire & d’Application de la Cavalerie et du Train via Wikimaginot

Categories
WW2 French AT Weapons

Canon de casemate 37mm Modèle 1934

ww2 French Tanks France (1931-1940)
Fortification Anti-tank Gun – 145 Produced

One of the most famous aspects of France’s interwar military, often parodied but quite seldom truly studied in English-speaking circles, is the fortification complex known as the Maginot Line, placed at the border between France and Germany. An extensive defensive line constructed from the late 1920s to the mid-1930s and further extended in the following years, this defensive line is mostly known in popular history for having been bypassed by the German push through the Ardennes and Benelux.

The Maginot Line is a far more complex and nuanced subject than most popular history circles make it out to be though – notably, while a powerful line, it was in some ways more makeshift and less state-of-the-art than one may expect, or, at the very least, not that well planned. This is, for example, the case when it comes to the line’s anti-tank firepower. The Maginot Line made large use of old 47 and 65 mm naval guns disposed of by the navy. The army operated them in an anti-tank role. Two purposefully-designed anti-tank guns were still designed for the Maginot Line, though they would be very late in being mounted. Both were designed by APX, the 47 and 37 mm Canons de casemate modèle 1934.

A view of the gun itself. An 8 cm thick mask would fill the firing opening and separate the inside and outside of the casemate when the gun was in place. Source: maginot.org

Inception of the Maginot Line

Despite the 1919 Treaty of Versailles deeply weakening Germany, with the German military reduced to a small, rump force officially devoid of tanks or planes, in the eyes of French military planners, Germany remained a constant possible threat in the future. Even cut down to size and officially prevented from expanding its military, Germany remained a far more industrially powerful nation than France – in fact, the only nation that could eclipse France’s industry on its borders. The threat of a future rearmed Germany was considered very serious, and outfitting France to fight such a potential future enemy was a significant concern for French military planners.

As aforementioned, the German industry far outclassed France’s, and it was thought that France could not hope to stand on even ground with a re-armed Germany. However, Germany lacked the resources of a colonial empire, and, particularly with British support, could be prevented from accessing many foreign resources with a tight blockade. In these conditions, France would only have to hold for long enough for Germany’s industry, military, and will to fight to be weakened by a blockade. A defensive line on the French-German border was thought of as a good way to even out the playing field and allow for France to stand up to the more populous and industrial Germany for long enough.

After extensive debates in the early 1920s, a commission, the CDF (Commission de Défense des Frontières – Borders Defense Commission) was created to take care of the matter in late 1925. After identifying the major parts of France’s borders where fortification complexes would be needed and after starting to plan out major fortification lines, the CDF gave way to a new commission to manage the construction of fortifications on a smaller scale. This would be the CORF (Commission d’Organisation des Régions Fortifiées – Fortified Areas Organization Commission), created in August of 1927. This CORF would be the organization managing the construction of the Maginot Line from 1928 to 1935, including all the equipment which would be used to outfit the defensive line.

A CORF casemate which was equipped with a machine gun/37 mm armament, Sinnersberg, France. Source: Mathieu Stenger via Wikimaginot

The construction principles of the Maginot Line

The Maginot Line would be an in-depth defensive line, about 10 to 15 kilometers deep from the border.

On the border, small casemates would be located and used by border guards. These were only small fortifications and not meant to offer any form of viable resistance. They instead served as warning posts of an incoming attack and were used for border guarding roles in peacetime. In the few kilometers behind these small casemates, further small holding points and obstacles were located to slow down an enemy advance towards what would be the true core of the Maginot Line: the LPR (Ligne Principal de Résistance – Main Resistance Line). This LPR was constituted of an alternance of small infantry casemates as well as larger fortifications of varying size which would operate artillery of various types. Behind the LPR, some infantry observation posts and fortifications for resting troops could be found.

The Maginot Line’s anti-tank guns were, for the vast majority, to be installed on the LPR. During the construction of the line, the creation of dedicated casemates which would only host anti-tank guns was considered for a while, however, this solution would not be picked as the standard. Instead, casemates would be able to alternatively mount an armament of anti-tank guns or machine-guns. Work on anti-tank guns designed with these specifications in mind started at Arsenal de Puteaux (APX) in 1931.

The adoption of a 37 mm anti-tank gun

APX originally started working on a 47 mm gun – which would also be adopted as the model 1934. However, this piece quickly turned out to be a fairly large and heavy gun, and it was thought that it would end up being too late to be reasonably operated in many casemates. As such, work quickly began on a smaller and lighter gun that would be used in smaller fortifications.

A view of the 37 mm model 1934 seen from the left, showing the gun’s attachment to a bi-rail beam, which would be installed on the ceiling of the casemate housing the gun. Source: Notice provisoire

The first APX 37 mm anti-tank gun prototype was tested in May of 1933 – preceding the 47 mm prototype, which would be tested later this year. Trials appear to have been successful, and both anti-tank guns would be adopted in 1934. However, the industrial process for both guns would be particularly long. Despite being adopted in 1934, the first production 37 mm anti-tank guns would only be delivered in the Spring of 1937, to be used for crew training. Only a small production run of the 37 mm gun was to be conducted. The 47 mm was seen as the standard weapon, with the 37 mm serving as a replacement where the larger gun could not be mounted. Deliveries of the 37 mm model 1934 gun would be completed in the spring of 1938. 145 37 mm model 1934 anti-tank guns would be mounted in Maginot Line fortifications, in comparison to 336 47 mm model 1934 anti-tank guns. It ought to be noted that, in comparison, 75 old 65 mm (models 1888/1891 and 1902) and 434 old 47 mm (models 1885 and 1902) naval guns would also be used in an anti-tank role on the Maginot Line, albeit in smaller and less important fortifications than the modern guns.

Properties of the artillery piece

The 37 mm model 1934 gun was designed to serve an anti-tank role exclusively and was, as such, optimized for this task. This resulted in a long barrel (2.088 m, or L/56). This barrel was rifled, with 12 twists, angled at 7° towards the right.

The barrel, which was given a fairly thick protecting shroud in order to protect it from damage caused by enemy fire. Source: Notice provisoire

This barrel would be used to fire the model 1936 37×278 mm armor-piercing capped (APC) shell. This was a 900 grams projectile that would be launched by 280 grams of propellant, granting a high muzzle velocity of 850 m/s. At one kilometer, this shell would be able to perforate 30 to 40 mm of armor, though it is not specified whether this would be at normal incidence or at the standard incidence of 30°. This was, in any case, a respectable amount for a 1930s 37 mm anti-tank gun, particularly if it was at an incidence of 30°. A blank training shell was also issued. It appears a high-explosive shell also existed, but its high-explosive charge is unknown, as well as whether or not it was actually issued.

The trio of 37 mm shells designed for the model 1934 gun. From left to the right, the armor-piercing, training, and high-explosive shells. Source: tir-collection.com

The model 1934 anti-tank gun used a semi-automatic action. The gun would recoil thanks to two hydraulic brakes, one located over the barrel to the right, and one under it to the left. The casing would be ejected from the breech into a collecting system which was set up by a servant, allowing for the introduction of a new shell.

The particularities of mounting the gun in a fortification

The 37 mm model 1934 was designed to be mounted in casemates, and was to be interchangeable with a dual machine gun mount. This was done by a particular solution, mounting the gun to a bi-rail beam mounted on the ceiling of the casemate. This allowed the gun to be pushed around by the crew (with the gun, including all equipment, weighing about 500 kg).

A surviving 37 mm gun, showing the beam on which the gun would be moved around. Source: Wikipedia

Two different models of firing opening, the Trémie n°2 and Trémie n°3, existed for the 37 mm/dual machine gun duo. The practical difference between the two was the firing angles. On the n°2, the 37 mm had a lateral traverse of 42.3° total and a vertical traverse of -12 to +12°. On the n°3, the lateral traverse was the same, but the vertical traverse changed to -15° to +10°.

Switching from the anti-tank gun to the dual machine gun mount would leave the firing opening open for several minutes, meaning this could not be performed while under fire. In most fortifications, at least two firing openings existed, meaning that the machine guns could be placed in one opening and the gun in the other. If there were more weapons available (a machine gun pair and a gun) for a single firing opening, the standard procedure was to mount the gun during the day and replace it with machine guns during the night, under the notion that night operations would be conducted by small infantry formations rather than armored vehicles.

Crew and operation of the gun

The 37 mm model 1934, seen from the rear. The gunner would stand to the left of the gun, the loader to the right, and the aid-loader further behind the gun. Source: Notice Provisoire

Both the 37 and 47 mm anti-tank guns had a crew of three (gunner, loader, assistant loader), which could be raised to four by adding either the maintenance mechanic or a resting soldier during situations where rapid-fire was required.

The gunner of the piece was located to its left. In standard operation, fire would be ordered by the casemate-commanding officer, but in urgent situations, the gunner assumed the function of commander of the piece. The gunner would look through the gun’s sight, which was an APX L.653 sight. It allowed for a zoom of x2.5 and a field of view of 20.3°. The gunner would be tasked with aiming the gun. He would aim the weapon using two rotating wheels (one, located under the gun to the left, for the lateral traverse, and one to the level of the breech, to its left, for elevation). He would then remove the safety lever and press on the gun’s trigger to fire. After a firing phase, he would put the gun back in its ‘resting’ position, with the gun placed to fire at a range of 700 m.

The 37 mm model 1934’s breech block, showing the handle which the loader would use to open or close the breech. Source: Notice provisoire
A view of the gun from the right, showing the place the loader would take when operating the gun. Source: Notice provisoire

The loader, standing to the right of the gun, would be managing the breech. A handle could be found on the breech, allowing it to be opened or closed; the loader would operate this handle in order to allow the shells to be ejected.

The third crew member, the assistant loader, stood to the rear of the gun, would set up the receiving box in which spent cases would be ejected and would insert the shells into the breech opened by the loader’s action on the handle. He would also get the shells out of their storage boxes and place them on the cap. In rapid-fire operations, the additional fourth crew member would take over this part of the operation, and hand the ready-to-fire shells to the assistant loader for him to insert them into the breech. A well-trained crew could hope to fire around 20 rounds per minute.

Limited use outside of fortifications

Outside of use in the Maginot Line, very little was done with the 37 mm model 1934, despite the gun offering some potent anti-armor capacities. The larger 47 mm anti-tank gun featured in a number of armored vehicles projects, for example as the main gun of some dual-armament heavy tank projects from the late 1930s. However, the only project which appears to have used the 37 mm was the Renault VE Type P, a project for a casemate tank destroyer related to the AMR 33 reconnaissance tank. A prototype was completed in 1935, but the type was never adopted for service by the French military.

The Renault VE Type P, mounting a gun known to be a derivative of the APX model 1934 fortification gun, though likely changed considerably to allow operations inside an armored vehicle. Source: char-français

Conclusion – A decent anti-tank gun with no service life

The 37 mm model 1934 gun was a decent weapon for the standard of the 1930s. Though little more than a filler to be placed where the 47 mm could not, it was still powerful enough to deal efficiently with anything the German military could field by 1940. While, unlike the 47 mm, it would not have had the firepower to defeat even France’s heaviest tank, or remain relevant for several years after 1940, it would still be efficient against the Panzer I, Panzer II, and the models of the Panzer III and Panzer IV fielded in 1940, as well as the Panzer 35(t) and Panzer 38(t).

However, the gun does not appear to ever have had the chance to demonstrate its armor-piercing capacities in practice. The Maginot Line saw relatively little combat due to being, in its majority, bypassed by German forces going through the Ardennes – where some minimal fortifications, with no dedicated anti-tank guns, existed – or the Benelux. Later in June, and even July, seeing as some bunkers surrendered days after the official armistice, some moderate attacks were performed on parts of the line – occasionally from the rear – but there are no reports of the 37 mm (nor the 47 mm) gun ever firing a shot in anger against German tanks.

After the Line’s capture by German forces, there has been no known use of the 37 mm gun. While still powerful, it was installed in a very specific way and used a purpose-built shell not known to be found in any other gun, which would have made even re-using the gun in German fortifications a costly and not worthy endeavor – especially as only a limited production run of the gun was performed. Most were left untouched during the German occupation, and have been degrading or been stolen or scrapped since, though a limited number of pieces are known to have survived and still be present in a number of Maginot Line casemates turned into museums.

The ammunition used in the Canon de casemate de 37 mm modèle 1934
The gun from the left side
The gun from the right side. Both illustrations created by Stoneheartisk

Canon de casemate 37mm modèle 1934 specifications

Caliber 37 mm
Barrel length 2,058 mm / L/56
Barrel rifling 12 twists, 7° to the right
Barrel & breech weight 142 kg
Recoiling ensemble weight 170 kg
Total weight 500 kg
Muzzle velocity 850 m/s
Crew 3 (gunner, loader, aid-loader), raised to 4 in rapid-fire situations
Rate of fire Up to 20 rounds per minute
Shell type Armor-piercing capped
Projectile weight 900 grams
Charge 280 grams
Armor piercing capacities 30 to 40 mm at 1,000 m (unknown incidence)
Effective Range Estimated to ~800 m; sight markings for up to 1,500 m

Sources

Notice provisoire sur les matériels de 47 et de 37 de casemate Mle 1934 du 4 Mars 1939, Ministère de la Défense Nationale et de la Guerre, Direction de l’Infanterie, Paris, 1939

Wikimaginot:
Canon antichar de 37 mm AC modèle 1934
Genèse de la Ligne Maginot (1919-1927)
Les principes de conception de la ligne Maginot

Lignemaginot.com

Categories
WW2 French AT Weapons

Canon de 25mm Semi-Automatique Modèle 1934 (25mm SA 34)

ww2 French Tanks France (1934-1940)
Anti-Tank Gun – 6,000 Built

During the First World War, France was the most important producer and user of armored vehicles alongside Britain. As France started to produce its first tanks, starting from 1916 onwards, studies began concerning anti-armor weapons able to defeat similar vehicles, meant to be useful if French troops were to face enemy tanks. In those last two years of the war, a French Chef d’escadrons (Chief of squadrons), Filloux, designed some light, high-velocity anti-tank weapons: a 13 mm anti-tank rifle, surprisingly similar to the German Tankgewehr in concept, and a 17 mm gun that could be mounted on the carriage of the standard 37 mm SA 16 infantry support gun. Only one or two prototypes of this high-velocity gun were made in 1918. The gun fired a 17×209 mm cartridge at a muzzle velocity of 1000 m/s. While studies of this “17 mm Filloux” stopped with the conclusion of the First World War, they set a precedent for the concept of a small, high-velocity anti-tank guns in the French military.

The 17 mm Filloux anti-tank gun on the carriage of the 37 mm TR SA 16 infantry support gun, 1918. Source: French Military Archives (Service Historique de la Défense)

With the studies of the Filloux anti-tank rifle and gun discontinued, and similar anti-tank projects, such as Delaunay-Belleville’s 20 mm “anti-tank machine-gun”, remaining at prototype stage, the French Army had to rely on the 37 mm TR SA 16 gun to defeat enemy armor. This gun, the field gun model from which the FT’s 37 mm SA 18 gun was derived, was a low-velocity infantry gun, with lackluster accuracy and penetration against armored targets. It quickly became clear that, against an army well equipped with tanks, this gun would be vastly insufficient. In 1921, France launched a program which envisioned both a 15mm dual-purpose anti-tank and anti-aircraft machine-gun, as well as a dedicated high-velocity anti-tank of a caliber smaller than 37mm. This program would fail to result in the adoption of an anti-tank gun. The 13.5mm machine-gun requirement would result in the 13.2mm Hotchkiss, which was used strictly in an anti-aircraft role. Meanwhile, in 1927, the state workshop of APX offered a 20mm anti-tank gun; but the caliber was found to be too small to result in sufficient armor-piercing capacities. New specifications were issued in 1928, this time clearly requesting a 25mm semi-automatic gun. This program requested a gun able of firing a 350 grams cartridge at a muzzle velocity of at least 700 m/s. This should be able to pierce at least 25mm of armor at an incidence of °20 and a range of 600 m. Draconian weight requirements were placed on the gun: it should not be heavier than 175 kg, and offer the possibility to be dismounted into 4 parts for easier transport. These requirements proved too hard to accomplish while retaining good armor-piercing capabilities, and were eventually disregarded. Prototypes from both APX and Hotchkiss would be pursued; the Hotchkiss design would finally be adopted in 1934. The adoption was likely motivated by fear caused by the rise of the Nazis in Germany, as well as the beginning of modernization and expansion of Soviet and Italian tank forces.

A prototype of the 25 mm Hotchkiss anti-tank gun Source: CAAPC (Centre des Archives de l’Armement et du personnel) via the ATF40 forum

Small Shell, High Velocity

Hotchkiss’s anti-tank gun was a low-caliber one, even for the era. While most anti-tank guns of the 1930s exceeded 37 mm, the SA 34 fired 25×193.5 mm rimmed projectiles, which French documents refer to as cartridges, and not shells. The gun had a 1.8 meter, 72-calibers long barrel, resulting in a high muzzle velocity of 950 m/s.

The standard anti-tank shell of the 25 mm SA 34 was a 900 grams cartridge with a 320 grams projectile. It had a tungsten core, surrounded by an internal shell of hardened lead, and an external shell of brass. The propellant powder contained in the cartridge was 138 grams, which was sufficient to be considered “charge forte” (high charge). With the socket, the cartridge had a length of 193.5 mm. The projectile itself was 109 mm long. French tests of this cartridge indicated a penetration of 40 mm on a vertical steel plate at 500 m, and 32 mm on a plate at an angle of 35° and a range of 200 m. German tests performed with captured guns give a more extensive range of values: against a vertical plate, the shell penetrated 47, 40 and 30 mm of armor at 100, 500 and 1,000 meters respectively. At 30° degrees, the penetration values were of 35, 30 and 20 mm; finally, at 45 degrees, they were 18, 16 and 15 mm. A tracer variant of the shell, offering almost equal performance, was also issued, apparently existing in red or white variants. The non-tracer armor-piercing cartridge was designated Balle P (for perforant), whilst the tracer armor-piercing cartridge was designated Balle TP (for traceur-perforant)

German documents on the trials of the 25mm SA 34’s Balle P anti-tank ammunition, from Kennblätter fremden geräts heft 8a, Munition bis 3,6 cm, Berlin, 1941. Image: German National Archives

Two cartridges with different projectiles existed, but were designed not for combat, but instruction: the Balle PR (for portée réduite – reduced range) had a smaller, steel projectile, and the Balle O (for ordinaire – ordinary) had a less strongly hardened core, being otherwise identical to the standard Balle P. A blank cartridge with reduced charge also existed. In operations, only P and TP projectiles were issued to the gun. There were no explosive projectiles and, as such, the 25 mm Hotchkiss gun was ill-suited for fighting against enemy infantry.

Figure showing the various types of projectile as well as the standard Balle P and its tungsten core, extract from the Notice d’instruction de l’école des chars de combat, 1937, via the French National Library/Gallica

The sights used on the 25 mm SA 34 were the lunette L.711 APX modèle 1936, which offered a 4x magnification, 11° field of vision, and markings for firing at up to 3,500 m. It was not fixed to the carriage, and was carried in a separate case. If it was missing, or damaged, backup notches on the barrel could be used to establish the proper elevation to fire at 400, 600, 800 and 1,000 meters.

The view offered by the APX L.711 sights. Extract from the Notice sur le canon semi-automatique “Hotchkiss” de 25mm du 2 Janvier 1935, in its 1937 edition, by the Ecole Militaire & d’Application de la Cavalerie et du Train

The gun was mounted on a small split-trail carriage, which, deployed, gave it a 60° field of fire, a maximum depression of -5°, and maximum elevation of 15°. The gun had a small profile, being 1.10 m high at its highest, while being 1.05 m wide when deployed. The carriage was typically towed ethier by hippomobile traction (horse-drawn), Renault UE logistical tankettes, or other motorized tractors. In motorized traction, it was specified that the speed should not go over 15 km/h, higher speeds bringing risks of damage for the quite frail carriage. The gun shield was 7 mm thick, and the gun on its carriage had a weight of 490 kg. The 25 mm gun had a semi-automatic action, with the only required actions from the crew being the introduction of a new cartridge and the firing of the gun. As such, the 25 mm SA 34 could achieve a quite high rate of fire. In the French Army’s manual for the gun’s operators, it stated that 18 to 20 rounds per minute could be reached, and figures of up to 25 rounds per minute against stationary targets are sometimes mentioned.

The transportation of a 25 mm SA 34 gun by its crew. Used only for very short displacements, the small size of the gun allowed this technique to be carried out much more easily than with the larger 47 mm anti-tank guns. Source: Le Canon de 25 mm antichar modele 1934 Hotchkiss, François Vauvillier

French Anti-Tank Use

French documents published in the late 1930s, such as the user manual, lay out the principles under which the gun was to be used. Unsurprisingly, they recommend the use of the gun’s low profile, fairly good mobility and small dimensions to hide in unexpected emplacements.

The manual also gives the recommended ranges to start firing on enemy targets. While purely indicative and depending on the conditions, the notice notifies that firing on tanks should begin at a maximum range of 800 m, while armored cars and other lightly armored or unarmored vehicles could be engaged at a maximum range of 1,250 m.

The crew of the 25 mm SA 34 was comprised of six: a commander, a gunner placed to the left of the gun, a loader placed on the right, and three additional servants. If the gunner was knocked out, his replacement was the loader, and if the loader was knocked out, he was replaced by the second servant, who otherwise cleaned and handed over the 25 mm cartridges from the crates. In practice, the gun could remain reasonably effective with two crew members, and still be operated, albeit with a much lower rate of fire, by a single crew member.

Staged photo showing the operation of a 25 mm SA 34 gun. As the photo suggests, only two crewmembers, the loader and gunner, really are actively operating the weapon. Source: Le Canon de 25 mm antichar modele 1934 Hotchkiss, François Vauvillier

Derivatives

A number of variants of the 25 mm SA 34 were developed in the 30s to fulfill a variety of different roles. A version used in armored vehicles existed, designated as the 25 mm SA 35. This version of the gun was shortened to fit into small armored vehicles, being L/47.2 instead of L/72. While this would normally have reduced the muzzle velocity, it was compensated by giving armored vehicles cartridges with an increased charge, resulting in almost identical muzzle velocity and penetration between the armored vehicle and field gun variants of the gun. The 25 mm SA 35 was not the most common armored vehicle gun though, as it only featured in a few cavalry armored cars and tanks, such as the AMD 35/Panhard 178 reconnaissance armored car, the anti-tank variants of the AMR 35 reconnaissance light tank, and six of the twelve AMC 34 cavalry tanks; generally, it was used in turrets which were too small to host larger guns such as the 47mm SA 35.

A side view of a Panhard 178/AMD 35 armored car, showing the shorter 25 mm SA 35 gun. Source: chars-français.
AMC 34 of the Chasseurs d’Afrique in Morocco. Six of the twelve Renault YR AMC 34 cavalry tanks produced were armed with the 25 mm SA 35 gun. Despite their lower caliber, those were far more effective than the vehicles armed with low-velocity 47 mm SA 34 against tanks, though the AMC 34 never encountered an enemy tank it its service life, nor an enemy to begin with. Photo from lesffi.vraiforum.com

A much more common variant of the 25 mm SA 34 was the SA-L 37. Designed by the state workshop of APX (also known as Puteaux) and offered as early as 1936, the SA-L 37 was a lightened model of the original Hotchkiss gun, designed specifically for infantry use. It was easier to move around for the six-men crew. The gun was considerably different from the original 25 mm SA 34. It was a lot lighter, weighing just 300 kg in all, making it one of the lightest anti-tank guns of the Second World War. In order to maintain the same performances despite this lighter construction, the gun featured a longer, 77 calibers, 1.92 m-long barrel. The carriage provided more depression and elevation than the Hotchkiss carriage (-10° to +26°) while keeping the same 60° field of fire. It used a foldable shield with an irregular top, as to make it harder to identify as a man-made object and to spot. However, the lighter construction meant that the gun was even more fragile, with motorized traction being prohibited, and only horse-drawn transport under 6 km/h being allowed. Despite those limitations, the lightened APX model was produced alongside the Hotchkiss model, being adopted as the SA-L (L stands for léger, light) 37 in 1938. In theory, the APX model was to equip the infantry, while the Hotchkiss was to be used by motorized and mechanized units. In practice though, the production of the APX models, while it reached more than a thousand examples in 1940, was not sufficient to fulfill the enormous need of the infantry, thus the more widespread Hotchkiss 25 mm SA 34 was a common sight among infantry divisions.

An APX SAL 37 gun at the Saumur tank museum. The SA-L 37 is easy to differentiate from the 25 mm SA 34 thanks to the different barrel, shield, and muzzle brake.- Picture by Rama via Wikimedia commons.

A fortification variant of the 25 mm anti-tank gun was also developed for the Maginot Line, being interchangeable with a twin MAC 31 7.5mm machine gun. It was used in a number of bunkers, but appeared to have been less common than the 37 mm and 47 mm RF fortification anti-tank guns.

In the Battle of France

In the spring of 1940, the 25 mm SA 34 was, by far, the most common anti-tank gun of the French Army. Including SA-L 37 guns, about 6,000 25 mm field anti-tank guns had been manufactured. While some three hundred had been delivered to troops of the British Expeditionary Force, and 400 may have been exported to Turkey, there was still a large quantity of guns in French service.

25mm SA 34 operated by the Royal Irish Fusiliers on a firing range, France, 1940. Imperial War Museum collections via Wikimedia Commons

It should be noted that the gun was used not only in France, but also during the Norwegian Campaign. An interesting anecdote is that the only German Neubaufahrzeug multi-turreted tank to ever be knocked out in combat, one of the three vehicles of that type that had been sent to Norway, was the victim of a British 25 mm Hotchkiss, which also knocked out its accompanying Panzer II light tank escort.

Two photos of British 25 mm SA 34 in 1940, 1st Royal Irish Fusiliers, from the Imperial War Museum’s collections via Wikimedia Commons
French 25 mm SA 34 crew, from the 20th issue of French magazine Le Miroir, January of 1940

The 25 mm SA 34 had both some considerable advantages and flaws in operation. Its armor-piercing capacities, while inferior to the excellent 47 mm SA 37 anti-tank gun that had started to enter service in the last years of the interwar, could easily handle the most common German tanks, which were still the Panzer I, Panzer II, and Panzer 35(t) at the time of the German invasion of France. The Panzer 38(t), Panzer III and Panzer IV, as well as the StuG IIIs, could be challenging to penetrate at the theoretical engagement range of 800 m, but were still far from invincible for the small French gun at closer ranges.

A Royal Irish Fusiliers 25mm SA 34 firing during training, France, 1940. Source: Imperial War Museum via Wikimedia Commons

Instead of being fired at the intended range of 800 m though, 25 mm SA 34 guns often operated at far shorter ranges. French tank historian Stéphane Ferrard referred to the 25 mm SA 34 as a “wood corner gun”, which was typically used at 600 m meters or less – the majority of tank combat happening at this range and lower in 1940. In those conditions, the 25 mm SA 34 could also fairly reliably penetrate the Panzer III and IV.

Royal Irish Fusiliers moving a 25 mm SA 34 gun around, 1940. The gun’s lightweight and small size made it quite easy to move and to conceal; the SA-L 37 version was even easier to conceal and move around, at the cost of high-speed towing capacity. Source: Imperial War Museum via Wikimedia Commons

The small size of the 25 mm projectile did mean that, quite often, enemy tanks would be knocked out, but not destroyed. Typically, side hits, where the thinner side armor did less to slow down the projectile and therefore its impact, did result in the destruction of enemy tanks, but even frontal penetration only resulted in the tank being immobilized, but potentially repairable. As a result, quite a number of vehicles penetrated by 25 mm SA 34 guns were recovered and repaired by German troops during or after the campaign. However, it should be noted that the 25 mm guns were often used in cooperation with a number of other anti-tank devices, such as the more powerful 47 mm SA 37, or anti-tank mines. The accurate and quick-firing 25 mm SA 34 could, when coordinated with other artillery pieces, immobilize enemy tanks, making them easy targets for larger anti-tank guns.

A 25mm SA 34 laying in ambush in a building in the city of Epinal, 1940. Source: 201day.wordpress.com

Despite this relative effectiveness, the 25 mm anti-tank gun did little to prevent the defeat of France against a German army that was generally better equipped and led by better tacticians. The vast majority of guns were abandoned or knocked out during the campaign, and while crews could occasionally perform quite well, that was far from sufficient to prevent a disaster years in the making.

An abandoned SA-L 37 at a crossroads in Nord-Pas de Calais, May of 1940. Source: Tank Archives

It should be noted that, as a result of the gun’s poor mobility when towed, the “portee” system came into use, developed in both the British and the French armies during the campaign of France. The 25 mm SA 34 would be loaded onto the rear of a truck, and used as a mobile, motorized anti-tank vehicle. The British would go on to widely use this system with their own 2 and 6-pounders guns in the North African campaign. In the last stages of the campaign, a conversion was also devised in France to mount the 25 mm SA 34 on the back of a Renault UE, the only photos of such a vehicle show it captured by German troops.

A 25 mm SA 34 gun loaded onto the back of a Laffly S20 TL during the campaign of France. Source: warmotors.ru
Two photos of a British 25 mm SA 34 being loaded onto the rear of a Bedford truck of the 1st Royal Irish Fusiliers. From the collections of the Imperial War Museum via Wikimedia Commons.

Beyond 1940 and Beyond France

Thanks to its large production numbers, the 25 mm SA 34 and its lightened model, the SA-L 37, remained in service for a number of years after the campaign of France, in a variety of different countries, including several nations of the Axis and other German allies.

One of the first foreign users of the 25 mm anti-tank gun was Finland. 50 guns had been ordered from France prior to the outbreak of the Winter War (December 1939-March 1940), in order to reinforce the Nordic nation’s anti-tank capacities against a Red Army that had the largest tank force in the world at that time. Out of those 50 guns, 40 arrived in Finland, of which only 20 had time to be used on the frontlines prior to the end of the war. 10 others were transiting through Norway during the German invasion, and were subsequently captured by the Wehrmacht.

After the end of the Winter War, Finland was able to purchase captured guns from Germany, over 200 in total, of which 67 were SA-L 37s. Designated 25 PstK/34 and 25 PstK/37, and nicknamed “Marianne”, the French anti-tank guns were widely used in the early phases of the Continuation War; 3 of them would be lost in action. Their penetration made them fairly capable against Soviet 1930s tank such as the T-26, BT series and T-28s. However, once those started to be massively replaced by T-34s and KV-1s, the 25 mm guns became completely obsolete, being phased out from the frontlines towards 1943. They were nonetheless kept in Finnish inventory and would remain there until 1959. They were declared obsolete and removed from inventory that year; the next year, 225 guns alongside 209,505 runds of 25mm ammunition were sold to International Arms Dealer Interarmco. Most 25mm guns in civilian ownership or museum collections far from France and areas where German troops used 25mm anti-tank guns are there as a result of sales by Interarmco.

The crew of a 25 pstk/37 anti-tank gun, July 1st 1941. Photo by TK-Sikanen via www.finna.fi
A 25 Pstk/34 anti-tank gun in service with the Finnish army, exact date and location unknown. Source: www.finna.fi
Finnish photo of a 25mm gun in operation, taken on February 11th 1942 by Ylikersantti Orvo Kärkönen in Impiniemi. Notice the very visible L.711 sight. Source: Jälkaväen raskat aseet ja ryhmä-aseet by Markku Palokangas

Germany had captured a number of 25 mm guns, likely in the thousands, with the Fall of France. As with the vast majority of captured French equipment, the anti-tank guns were put into second-line service for German troops. Designated Pak 112(f) for the SA 34 and Pak 113(f) for the SA-L 37, the French guns were typically issued to second-line units operating in the Balkans or in Norway. They were also used on the Atlantikwall. The French anti-tank guns were quite often used alongside their original tractor, the Renault UE. Following the example of a French conversion designed in the last weeks of the 1940 campaign, German troops did also mount the 25 mm on Renault UE to create a makeshift tank destroyer; the same conversion is known to have existed on the hull of the Universal Carrier in North Africa.

A captured Universal Carrier with a Pak 112(f) gun, North Africa. Source: beutepanzer.ru
A park of captured 25 mm SA 34s in the spring of 1940. Source: Tank Archives
Use of the Renault UE (Infanterie UE-Schlepper 630(f)) alongside the Pak 112(f). Source: Tank Archives
Two photos of Pak 112(f) used on the Atlantikwall. Source: www.ww2enimagenes.com

It is also known that some guns were delivered by Germany to Italy, where, in Italy’s designation system, they were given the name of Cannone da 25/72. 150 guns of the SA-L 37 model were sold to Spain in 1943, alongside a variety of other military equipment, including small quantities of Panzer IV Ausf. H tanks and StuG III Ausf. G assault guns. It appears small quantities of 25 mm SA 34 may previously have seen service with Republicans forces during the civil war.

The 25 mm SA 34 and SA-L 37 were retained in Vichy French service as well, forming the backbone of the anti-tank defences of the French Levant during its invasion by Commonwealth and Free French forces in June and July of 1941. A good number of these 25 mm guns, alongside many small arms and 75 mm mle 1897 field guns, were subsequently captured, and passed onto the Free French 1st BFL (Brigade Française Libre), which was mostly comprised of French veterans, many of which had experience operating those guns. The 25 mm guns were notably widely used during the Battle of Bir Hakeim, both as field guns and mounted on a variety of different hulls, such as Marmon-Herrington armored cars or Universal Carriers. The 25 mm guns would only be phased out from French service at the end of the North African campaign in 1943, and it is likely some re-captured guns were shortly used by makeshift units of the FFI (Forces Françaises de l’Intérieur – French Forces of the Interior) resistance during the Liberation of France

Free French Universal Carrier armed with a 25 mm SA 34 anti-tank gun, circa 1942. Source: Institut National de l’Audiovisuel via leadadventuresforum
Free French Universal Carrier, fitted with a 25 mm SA 34 in an unusual configuration putting it above the Carrier’s structure and keeping the gun shield, Syria. Source: char-français
Free French Moris 15CWT truck fitted with a rear-mounted 25 mm SA 34 including gun shield. Such vehicles were named “Derviche”, after a type of muslim religious figures. Source: leadaventureforum
Free French Marmon-Herrington Mark III. Two out of three vehicles retained the Boys anti-tank rifle, while the others featured the 25 mm SAL-37 anti-tank gun. Source: leadadventureforum
Marmon-Herrington armored car of the Afrika Korps with a 25 mm SA 34 gun with shield replacing the turret, with Commonwealth soldiers in front. Whether the conversion was Free French and then captured by German troops or originated from them is unknown. Source: www.worldwarphotos.info

As for other operators, while the United States never used the 25 mm SA 34 in combat, a small number of guns had been purchased for trials in the 1930s. Interestingly enough, it appears some of those guns were then placed along a small monument which very shortly appeared in a clip of the 1985 film Back to the Future, giving the small French anti-tank gun an appearance in a classic of science-fiction cinema.

Two 25 mm SA 34 briefly seen in Back to the Future, 1985. Photo: Universal Pictures

Conclusion

The 25 mm SA 34 was, during the Battle of France, the most common anti-tank device used by the French Army, playing in that sense a similar role to the German PaK 36 or the British 2-Pounders. In that role, it was a fairly decent weapon, which contrasts with some of the very lacking equipment operated by the French military, such as the Renault R35/R40 and Hotchkiss H35/H39 light tanks. The 25 mm SA 34 was indeed a small, fairly easy to operate and accurate gun, and while its small caliber was destined to obsolescence fairly soon, against the armored vehicles operated by the Wehrmacht in 1940, high-velocity 25 mm shells were still powerful enough in the majority of situations.

After the end of the Campaign of France in June of 1940, the 25 mm SA 34 and its SA-L 37 variant found themselves being used as a secondary anti-tank gun in a variety of militaries on both sides of the war, however, by 1941-1942, the gun became increasingly useless against newer models of tanks being introduced, such as the T-34, M4 Sherman, and newer models of Panzer III and IV. With neither a caliber high enough to give the gun much of an evolutionary potential, nor an industrial base remaining to study and produce such potential improvements, the 25 mm anti-tank gun remained confined to secondary fronts and internal security, despite its lack of high explosive shells also being a handicap in this domain. With the war concluded, it seems that the small anti-tank gun did not see service beyond 1945, unlike some other pre-1940 pieces of French equipment such as the Panhard 178 which, fitted with a new turret armed with a 47 mm SA 35 gun, soldiered well into the 1950s.



Illustration of the Canon de 25mm Semi-Automatique Modèle 1934 (25mm SA 34).


Panhard 178 armed with the 25mm SA 34. This is an early production vehicle of the 6th GRDI, 2nd Squadron, France, May 1940


AMR 35 ZT-2 tank hunter, armed with a 25 mm SA 35 in an APX 5 turret (built at Atelier de Rueil) with a secondary 7.5 mm Reibel coaxial machine gun. Only ten built after production dragged on until 1940. AMR 35 ZT-2 and ZT-3 were used alongside machine gun armed ZT-1 in Dragons Portés (Motorized Dragoons) regiments, to give them armored and mobile anti-tank escort.


AMR 35 ZT-3 SPG tank hunter, which was armed not with the shorter SA 35, but the longer SA 34 in a casemate. Ten were built at APX (Ateliers de Puteaux) until September 2, 1939.

All illustrations were produced by Tank Encyclopedia’s own David Bocquelet

Specifications (SA 34 & SA-L 37)

Weight (Deployed) 490 kg (SA 34), 300 kg (SA-L 37)
Length (With Carriage) 3.71 m (SA 34), 3.46 m (SA-L 37)
Height 1.10 m (SA 34), 1.03 m (SA-L 37)
Width 1.05 m (SA 34)
Calibre 25 x 193.5 mm
Barrel Length L/72 (SA-34), L/77 (SA-L 37)
Traverse 60°
Elevation -5° to +15°
Rate of Fire 8 – 20 rpm, up to 25 rpm with a well-trained crew
Sight Range 3,500 meters
Effective Range 800 meters

Penetration Figures (Balle P, German tests)

100 Meters 47 mm @ 0°
500 Meters 40 mm @ 0°
1000 Meters 30 mm @ 0°
100 Meters 35 mm @ 30°
500 Meters 30 mm @ 30°
1000 Meters 20 mm @ 30°
100 Meters 18 mm @ 45°
500 Meters 16 mm @ 45°
1000 Meters 15 mm @ 45°

Sources

Notice sur le canon semi-automatique “Hotchkiss” de 25mm du 2 Janvier 1935, in its 1937 edition, by the Ecole Militaire & d’Application de la Cavalerie et du Train via Wikimaginot
German documents on the trials of the 25mm SA 34’s Balle P anti-tank ammunition, from Kennblätter fremden geräts heft 8a, Munition bis 3,6 cm, Berlin, 1941
Notice d’instruction de l’école des chars de combat, 1937, via the French national Library/ Gallica
Le canon de 25 allégé APX modèle 1937, 1940, Saint-Cyr military school
ATF 40 forum post by historian Stéphane Ferrard
tankarchives.blogspot.com
beutepanzer.ru
wikimaginot.eu
Free French 25mm-armed tank destroyers
www.chars-francais.net