The French 75mm Gun

Perhaps no gun in the twentieth century was as influential as the French canone de 75mm Modelle 1897.  When it was first introduced, it was a decisive improvement over the artillery of all other nations.  By the outbreak of the First World War, its secrets had been imitated by the other belligerents, but its usefulness was limited more by the nature of trench warfare than by any erosion of the French advantage.  Where circumstances favored the use of light field pieces, the 75mm gun earned its reputation.

Field artillery consists of guns light enough to travel with an army on the march, and light enough to be deployed on a battlefield while an engagement is being organized.  “Light” is a relative term; teams of horses were needed to pull these guns into position.  Gun crews moved the gun to aim at targets they could see from their own position, and traditionally, this needed to be done every time the gun was fired because the recoil of the shot moved the gun out of position.  For several reasons, the French M1897 was a substantial improvement.

Most importantly, the “soixante-quinze” (“seventy-five”) featured a hydraulic system to absorb the recoil.  With the gun carriage further reinforced by digging in a spade built into the rear and brakes attached to the wheels, the M1897 would remain in place after firing, allowing the gun to be reloaded and fired again without being manhandled back into position.  It is this feature that gives the M1897 its description as “quick-firing.”  This general characteristic also applies to the M1897’s imitators, but none surpassed its speed: it could reliably fire 15 rounds per minute, with rates exceeding 30 in emergencies.

The speed of reloading was also enhanced by its efficient Nordenfeldt breech mechanism.  The ejection of the empty casing and its replacement with a new shell was as fluid a motion, for artillery, as the operation of the turnbolt was for infantry rifles.  The M1897 limbers carried 72 rounds, which made for a good start when the battle was joined.  These rounds were high-velocity shells with high explosive or shrapnel warheads.  Against soft targets, the M1897 could deliver devastating fire at a withering rate.  It was designed to win the kind of engagements that the French anticipated at the turn of the century.

Ironically, the M1897’s recoil mechanism was built on the work of a German inventor, Konrad Haussner, who applied for his patent in 1881.  German work with the same basic mechanism was less successful, and so it came as a surprise when the French adopted the M1897.  In subsequent years, most of the other Great Powers developed their own alternatives to this gun.  Significantly, the United States had its own designs on paper in 1917, but few actual pieces, and so American forces copied Allied designs.  The French 75mm served the US Army in both World Wars, and along with two larger French guns, made a powerful impact on American artillery technology.

Expectations of the gun’s performance were very high when war broke out in 1914; furthermore, when the French were able to use the gun as intended, it performed very well indeed.  This allowed the French to build up the “75” into something of a wonder weapon.  It was not, however, well suited to the kind of conflict that dominated the First World War, especially in the West: trench warfare.  Field artillery in general was poorly suited to the trenches for three reasons: the size of the shells, the trajectory of the shot, and the need to sight the shot accurately.

By definition, light artillery fires small shells.  In the case of the 75, its shrapnel shells were only 16 pounds, while high explosive shells were slightly less than twelve pounds.  Against a squad of infantry in the open, or a squadron of cavalry, one of these shells could be devastating; against a bunker, or even infantry protected by a trench, these shells were much less dangerous.  Once the Germans began to dig in, the 75 offered limited utility until some measure of mobility returned to the battlefield in 1918.  It might also be noted that the quantity of ammunition produced for the 75 was never adequate.

Trajectory was also a serious limitation.  All artillery is fired in an arc, because gravity begins pulling the round to earth as soon as the round leaves the barrel.  To hit a given target, a shell must be shot higher than the target, so that it will fall to the appropriate elevation when it reaches the target.  While this is always the case, artillery can use a flat or steep trajectory.  Heavy guns and howitzers use steep trajectories; these shells fly far overhead and then fall to earth, hopefully near the target.  Such shots are comparatively slow, and they can be inaccurate, because the gunners are depending on coordinates given to them, rather than making their own calculations.  On the other hand, they can deliver heavier shot at greater distances, and the shells can fly over defensive walls (or friendly soldiers) and strike more vulnerable targets out of sight.  These advantages made heavy artillery more suitable to the demands of trench warfare.

In contrast, light artillery shoots smaller rounds in a relatively flat arc at a target sighted by the gun crew.  It can still fire across significant distances (the 75 could fire up to 9000 yards away), but the gunners still needed to see a target.  An infantry battalion taking cover in a trench was not a useful target.  Moreover, because the arc was shallow, the 75 could not fire into trenches or over significant walls.

Closely related to the question of trajectory is the issue concerning visibility.  The 75 was meant to be fired at a target selected by the gunners, based on battlefield conditions.  Opportunities to function this way became limited once the front stagnated into trenches.  When aerial reconnaissance became the primary means to select targets for the artillery barrage, the advantages of field artillery vanished and the heavier guns proved superior.

As a result of these considerations, the 75 performed admirably during the first few months of war.  Indeed, it played a powerful role in the Miracle of the Marne.  Here, it was able to operate in the way that the French had intended, and it exceeded its expectations.  By December, in the First Battle of Champagne, the 75 performed abysmally.  It did little even to eliminate the barbed wire that protected the approaches to the German trenches, let alone to soften up the principal defenses.  In 1918, however, it would have the chance to shine again, when Allied offensives in the fall created the opportunities for combat in the open.  A young Harry Truman led a battery of 75s during the Meuse-Argonne Offensive, and during that action, his battery fired its guns at the full emergency rate of 30 rounds per minute.   The 75 was again able to prove its worth.

Although outdated, the 75 continued to serve in a limited capacity in World War II; for example, American forces in the Philippines used them during the Japanese invasion.  It remained relevant for training purposes even after the war.  There was, however, another use for these guns that made up for some of their limitations: they could be used on an armored vehicle, which allowed the drivers to bring the gun to its targets.

In 1917, the French delivered one of their early tank designs, the Char d’Assaut St. Chamond.  Its main gun was an M1897 75 mounted in the nose.  While the tank itself proved inadequate, the use of the gun was sound.  During World War II, American forces mounted the 75 on a half-track, which made a name for itself as the Gun Motor Carriage M3.

While the “soixante-quinze” enjoyed some hype during the First World War, most of it was deserved.  Taken on its own merits, it was still a remarkable weapon fifteen years after its creation, and when used as intended, it could be decisive.  Even after it became obsolete, it continued to exert a powerful influence over future artillery development, both in the training of recruits and in the development of modern military vehicles.

 

Sources:

Dougherty, Martin J.  Tanks: From World War I to the Present Day. Sterling, 2008

Halberstadt, Hans.  The World’s Great Artillery: From the Middle Ages to the Present Day.  Barnes & Noble, 2002

Haythornthwaite, Philip J.  The World War One Source Book.  Arms & Armour, 1996

Livesey, Anthony.  Great Battles of World War I. Smithmark Publishers, Inc. 1997

Neiberg, Michael S.  The History of World War I: The Western Front 1914-1916.  Amber, 2012

Willmott, H.P.  World War I.  Covent Garden Books, 2003

 

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