WWII Tech Pubs Briefing

Written by
Duane Godwin

French gun crews rush to engage another low-level attack on an airfield in northern France, May 1940.

[ Top of Page | Feedback ]

Overview

The story of the 25-mm (0.98-in) Contre-aéronefs modèle 38 (Anti-Aircraft Model 38; CA mle 38) is yet another of poor French planning, official indifference, and production delays. The gun itself was a fine weapon, but it was ordered too late and was never numerous enough to make a difference in the Battle of France. They ended up used by the very country that they were intended to defend against. The Japanese, however, had been quick to see the new gun’s promise, and deployed tens of thousands of them.

The end of World War I left the French military with enormous stocks of leftover weapons. The French were obviously keen to recycle these weapons in future plans rather than spend money on new ones. World War I’s trench warfare had so coloured French military thinking that all French planning for future wars was geared to that sort of static combat, with little regard given to the type of fluid warfare that the Germans actually used in 1940. As a result, the French military felt that the existing guns that had served them well in the past conflict were ideally suited to the future. Planners drawing up requirements for anti-aircraft (AA) weapons envisaged a large-calibre weapon - a new version of the 75-mm (2.95-in) mle 1897 - for high-altitude defense, and a light machine gun for low-flying aircraft.

The Hotchkiss company disagreed with French doctrine, and designed a new 25-mm anti-aircraft cannon, which they put forward to the authorities in 1932. Hotchkiss met with an extremely negative response, but did manage to persuade the nilitary to at least test the new weapon. Nothing came of Hotchkiss’s endeavours for a few years, and it seemed as if that would be the end of the story – at least as far as the France was concerned. Hotchkiss pressed forward with plans to market the new gun to other countries.

In 1935, the Nihon Kaigun (Imperial Japanese Navy), dissatisfied with its Vickers 2-pr AA guns, settled on a variant of the Hotchkiss 25-mm AA gun as a replacement. They manufactured it under license in huge numbers (around 33,000 guns) as the 25-mm Type 96, and it became the standard shipboard AA gun. Although the Japanese navy had shown much technological aptitude in choosing the 25-mm Hotchkiss in the first place, that gun remained the heaviest automatic AA gun in Japanese naval use throughout the war, even though toward the end of the war, the Allies considered it too lightweight for serious AA use. The Japanese modifed the Hotchkiss design to take into account the corrosive nature of sea-going conditions (especially on submarines) and manufactured certain parts in stainless steel. Other changes included the use of castings and the fitting of Rheinmetall-type flash suppressors to each barrel. The Japanese used the guns in single, dual, and triple mountings.

The Spanish Civil War erupted in 1937, and combatants there introduced and proved new concepts and weapons. One of these new concepts was the use of AA guns as anti-tank (AT) weapons. Their flat trajectories and high muzzle velocities made them deadly killers of enemy armour when used with armour-piercing ammunition. The most famous example of this was the feared German “88” – the 8,8cm (3.46-in) FlAK 18, later developed into the 8,8cm FlAK 36 and 37, which destroyed thousands of Allied armoured vehicles in WWII in addition to attacking formations of aircraft in their original role.

French observers in Spain reported back to their masters, who suddenly realized that a light anti-aircraft cannon was most certainly going to prove very useful in any future European war and hastily placed an order with Hotchkiss. As could be expected from the French staff, however, there was great uncertainty about the exact requirements of the new gun, and it was late in 1938 before the details had been ironed out. In the meantime, the Rumanian government had placed an order for the new gun, and Hotchkiss was in full production fulfilling it. Hotchkiss had to hurriedly make the required changes for the French order, which meant interruption of production. Eventually, these problems were overcome and the guns began to come off the line. A version of the gun was also produced for the Marine nationale (French navy), to be placed on a pedestal mounting, although it seems that the Marine nationale never actually used them operationally.

As at many other French arms manufacturers at that time, industrial strife affected Hotchkiss even in the face of war. These troubles, and the other usual delays associated with mass arms production, meant that Hotchkiss was going to fall short of delivering the required number of guns. Only a little over 1,000 Hotchkiss 25-mm AA guns of both the mle 38 and mle 39 types were in service in May 1940 when the Germans invaded France and the Low Countries, far fewer than the French had ordered.

Armour-piercing (AP) shells were issued to all 25-mm AA batteries, which used them on the battlefield. Most of the German armoured fighting vehicles that these guns destroyed with AP ammunition were armoured cars. The fluid tactics of Blitzkrieg (lightning warfare) ensured that the thinly armoured German reconnaissance cars frequently encountered French AA batteries. Laffly W15 TCC self-propelled AT guns were protected by batteries of 25-mm CA mle 38s that scored kills themselves.

In a matter of weeks, despite desperate and brave fighting by the French forces, French leaders signed an armistice with the Germans in which they agreed to stop resistance and give Germany dominion over large swaths of France. One clause of the Armistice allowed the Germans to acquire huge amounts of war booty, and many 25-mm CA mle 38s and mle 39s were impressed into German anti-aircraft regiments. The captured guns mostly remained in France and many were later part of the Atlantic Wall beach defences. The Germans designated their Hotchkiss AA guns the 2,5cm Flugabwehrkanone (Aircraft Defense Cannon; FlAK) Hotchkiss 38(f) and the 2,5cm FlAK Hotchkiss 39(f). The Vichy French retained guns under their control.

The different versions of the Hotchkiss 25-mm AA gun were intended for very different roles. The 25-mm CA mle 38 was a highly mobile weapon on a light, two-wheeled carriage that set up with three legs. This weapon, while easily transported, suffered too frequent breakage when towed and so was usually carried on the bed of a truck. The Laffly S20TL truck, for example, could even deploy the gun in combat from its bed. The mle 39 was a similarly shaped but far heavier weapon intended for static mounts that had only limited mobility. A third version, the twin-barreled 25-mm CA mle 40, was in trials at the time of the Armistice. The model number is the year the design was finalised: 38 for 1938; 39 for 1939; etc.

For aiming, crewmen would use a Télémètre stéréoscopique à échelle fixe de 1.25 m de base (1.25-m-Base Fixed-Scale Stereoscopic Rangefinder) mle 1934 of 12x zoom capability and an Appareil orienteur tachymètrique (Tachymetric Predictor) mle 1934, then dial in results to properly offset the aiming point of the gunsight. The mle 38 used a DCA 939 gunsight and the mle 39 a DCA 951 gunsight.

[ Top of Page | Feedback ]

Specifications

[ Top of Page | Feedback ]