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Historic context :
Inspired by the works of the French captains Baquet and Locard, fathers of the very first gun equipped with hydropneumatic recoil recuperating systems, and by the ones of the German engineer Haussner, inventor of the barrel long recoil, the Puteaux Arsenal captain Sainte-Claire Deville de l'Atelier de Puteaux realised at the beginning of the 1890 years several promising prototypes of fieldguns of different calibers, giving way to a request by the French Headquarters of a new 75 mm modern gun.
The '75C' quick firing project of the commandant Deport from the Puteaux arsenal soon took the lead compared to others. It received the sponsorship of the Army Artillery Director and was kept secret thanks to a smart counter-intelligence program promoting the less promising projects named 75A, 75B and 75D. The first tests of the initial prototype in 1893 proved the amazing performances of the design. The demission of Deport in 1895, joining the private industry led by a disappointment caused by the lack of recognition by the Army, was an issue quicly solved by the project continuation by the captains Sainte-Claire-Deville and Rimailho, unconditionally helped by the General Deloye, new Artillery Director. This team bring the project to its term, giving birth to the revolutionary 'canon de campagne de 75 mm Mle 1897' (75 mm M 1897 fieldgun), officially adopted in 1898 but whose first tubes and carriages had already been ordered in 1895 and 1896.
The gun performances, particularly its fire rate (up to 18 rounds per minute), its range (6000 to 7500 m), its precision, its absolute stability when firing and its remarkable mobility (not to mention its futuristic profile) instantaneously made obsolte the fieldguns of the other nations, creating a panic wind in the design engineers and the headquarters. Thanks to it, France was completely turning the techological and tactical situation to its advantage, indeed washing the shame of the 1870 war defeat, partly caused by its artillery technological weakness.
Thes exceptional properties were given by numerous technological innovations, including the following most important ones :
- the hydropneumatic recoil recuperating system (hydraulic brake, pneumatic recuperator), precision mechanics assembly that was one of the best guarded secret until the end of the war, even with France allies,
- the tube long recoil allowed by the tube end rollers and craddle paths,
- the perfect stillness of the carriage thanks to the spade and the set-up 'abattage' technique consisting in putting the gun wheels on saddles firmly linked to the carriage)
- the eccentric single movement quick maneuvering Nordenfeld breech, with automatic extraction of the cartridge
- the ingenious pointing systems and mechanisms allowing the quick aiming simultaneously in direction and elevation by two separate servants, the pointer and the gunner
- the use of fixed munition (shell and cartidges pre-assembled) whose time and percussion fuzes could be quicly and error-free pre-set with a special box device named 'débouchoir'
Presented to the public in 1899, and shooting its first shells in combat in China in 1900, in front of stunned European nations observers, the 'mighty 75' seduced the French Army and governement so much than they arrived to the point they considered that this only gun 'sufficed to cover all the missions that can be given to the artillery in the field war'. This certitude, allied to the exclusively offensive doctrine adopted by the headquarter as well as budgetary reasons, led the nation to show very little interest to the modernization of its heavy field artillery, and completely abandon all the projects for a light field howitzer.
This would have very sad consequences as soon as August 1914 : even though the 75 confirmed during the whole war its impressive effectiveness against troops in a infantery support role, it was soon demonstrated ineffective against entrenchments (because of its flat trajectory fire) and in a lesser importance for artillery preparation missions (its explosive shell lacking power, despite being much superior to its German 77mm equivalent).
Numerous 'tricks' were improvised before and during the war in order to compensate this, including the shooting with reduced propelling charge, the trail placed into a pit, and the modification of the shell trajectory with the addition of a 'Malandrin' plate (aerodynamic brake) on the top of the shells. These ideas allproved disappointing, often causing human losses.
Beginning the war with 4780 such guns (4080 of them being directly available for operations), the 75 gun inventories felt to 3071 guns in may 1915 under the action of combat losses as well as the tube bursts crisis, caused by defective shells manufactured by numerous producers of various quality hastily mobilized. The inventories soon went up again thanks to the impressive war efforts in the Army arsenals assisted by the private industry (including Schneider) : 6039 guns were aligned in the French Army in November 1918.
Variants were designed as anti-aircraft weapons, anti-tank guns, coastal artillery, navy guns and fortress weapons (in the 'casemates de Bourges'). The 75 was to be used by numerous French allies during WW1, including Belgium and USA (1828 guns bought), but also by the German Army that used numerous captured guns for the fabrication of anti-aircraft guns. This gun was still in use in the French Army in may 1940, and participated afterwards to the war with the 'France Libre' troops in Africa, or was integrated in some units of the German Wehrmacht.
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Technical data :
- Complete description : 75 mm fieldgun M 1897
- Design year : 1897
- Calibre : 75.00 mm
- Weight in firing position : 1140 kg
- Weight for transportation : the same, plus the ammunition trailer having a similar weight, both towed together
- Tube length in calibres : 34.50 (2475 mm - 30 calibres rifled part only)
- Grooves : 24 to the right, constant 7 degrees angle
- Projectile weight : 5.3 kg (obus explosif normal) / 7.24 kg (obus à balles) / 7.98 kg (obus explosif allongé) / etc...
- Initial speed : 550 m/s (normal high explosive shell)
- Fire rate : 18 rounds / min (recommended 12 rounds / min max)
- Range : depending on the shell 6000 m / 6900 m / 11200 m / etc...
- Elevation range : -11 to +18 degrees
- Direction range : 5 to 6 degrees total range (100 thousandths)
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