The 75 mm. Field Gun
by
Ardill
The French Army, faced with the inadequate firing speeds of their standard artillery guns, sought a quick-firing solution with a more rapid re-aim capability. Then, in 1897,[1] artillery inventors such as Joseph-Albert Deport and Henri Étienne Sainte-Claire Deville[2] collaborated to create the game-changing 75 mm. field gun. The French Army adopted it in 1900,[3] when it was unveiled, reducing its standard battery of six artillery pieces to four “75s.”[4] The new weapon met the need for range, mobility, and versatility, while pioneering a revolutionary system to absorb and reverse the force of the firing gun, so that it did not leap back, like other guns of its era did.[5] While the new artillery was effective at the beginning of World War I, it lost effectiveness during trench warfare.
The new weapon weighed 1,100 kilograms,[6] and had a maximum range of 6500 m.[7],[8],[9] The 75-mm gun incorporated a barrel that was not welded onto the rest of the gun, a rotary breech,[10] and a revolutionary hydro-pneumatic recoil system. A piston connected from the exterior to the barrel. The firing of the gun pushed the barrel backwards, bringing the connected piston with it. The piston forced a special non-freezing mixture of water and glycerin[11] around a curve, where it pushed a floating piston forwards, which compressed an air chamber. The compressed air acted as a spring, pushing the floating piston back,[12] and, indirectly, the barrel. This prevented the artillery piece from lurching backwards during a recoil, making it safer and more reliable to operate. Its action is illustrated in the image below. In the first image, the gun is at ready. The second image shows the shell (black with a red tip) being fired, causing recoil, which pulls the piston connected to the barrel (red) back, which causes the glycerin-water mixture (orange) to go around a curve, pushing the floating piston (red) forwards, compressing the air (blue). The third image depicts the air (teal) pushing the floating piston back, forcing the glycerin-water mixture back around the curve, forcing the piston back, which pulls the barrel with it. This type of recoil mechanism had not been used in earlier weapons.
[Image pending permission for use]
[13]
The 75 mm. gun had a rotating block[14] with a hole that, when the block had been rotated to the correct position, lined up with the barrel, so that the old shell could be ejected by an automatic mechanism, and the new one inserted.[15] The cylindrical block was edged with gear-like teeth which allowed it to turn easily, and to resist the force of the explosion when the gun was fired.[16] A rotating handle on the block connected with a lanyard that, when pulled and released, would release a hammer to hit the striker in the gun, which would in turn hit the primer, firing the shell.[17]
[Image pending permission for use]
[18]
The gun could fire a wide variety of shells, examples of which are shrapnel and high-explosive shells. The high-explosive shell weighed 5.3 kg,[19] and could be fired to a range of up to 6500 meters.[20] A time-delayed explosion allowed the projectile to penetrate the target before exploding, causing greater damage.[21] In contrast, the shrapnel shell, or “robin” shell, weighed 7.2 kg,[22] and had a range of only 3250 meters.[23] It employed a more complex delay mechanism: when the “robin” shell hit the ground, the impact would ignite a short time-delay fuse, and the shell would bounce upward, exploding at a height of approximately 5 meters. The explosion would release 300 tiny lead balls, each weighing 12 grams,[24] in a cone-shaped pattern.[25] The lead balls could cover an area about 25m wide by 200 m deep, causing 50% casualties to enemies exposed to them.[26] With a rate of fire of about 20 times per minute, the 75-mm gun could bombard the enemy with about 6000 lead balls per minute,[27] each of which could travel along someone’s arm, or enter the ribcage, where it could bounce around, causing internal damage. The variety of shells made the 75-mm gun versatile in diverse situations.
The French Army in World War I, like many armies before it, developed standard techniques called tactics to handle various situations anticipated in the course of the war. One common artillery tactic was to fire five to six shrapnel shells per gun as fast as possible, and then wait for a random time, and then repeat.[28] The shrapnel shell was very effective against troops out in the open, but completely ineffective against troops in trenches.[29] The high-explosive shell was equally ineffective for trench warfare because of its size; troops could sit with their backs to the trench wall, safe from the 75 mm. field gun, or any similar weapon.[30] Other armies had developed similar artillery units: the British had the 18 pounder, and the Germans, the 7.7 cm FK 96 n.A.[31] The 75 mm. gun and other similar weapons encouraged the shift early in WWI to entrenched warfare, a warfighting context which rendered them much less effective.[32] However, the 75-mm. artillery piece would remain the dominant gun for the French Army, even into the Second World War.[33]
Sources
Footnotes
[1] H. P. McCain, ed., Notes on the French 75-mm. Gun (Washington, U.S.A.: U.S. Government Printing Office, 1917), 5.
[2] Ibid.
[3] Dale Clarke, World War I Battlefield Artillery Tactics (Great Britain: Osprey Publishing, 2014), 7.
[4] Ibid., 8.
[5] Bradley Meyer, “RE: Book recommendation request,” e-mail message to Ender Berberian, November 8, 2017.
[6] McCain, ed., Notes on the French 75-mm. Gun, 12.
[7] When firing a high-explosive (HE) shell.
[8] McCain, ed., Notes on the French 75-mm. Gun, 12.
[9] Clarke, World War I Battlefield Artillery Tactics, 8.
[10] Ibid.
[11] McCain, ed., Notes on the French 75-mm. Gun, 7.
[12] Ibid.
[13] Bernard Plumier, “THE ARTILLERY IN FIRST WORLD WAR,” March 29, 2004, http://www.passioncompassion1418.com/decouvertes/english_fusees_artillerie.html, (accessed Nov 6, 2017).
[14] Clarke, World War I Battlefield Artillery Tactics, 8.
[15] McCain, ed., Notes on the French 75-mm. Gun, 6.
[16] Ibid., 5.
[17] Ibid, 6.
[18] United States Army Ordnance Department, Handbook of artillery: including mobile, anti-aircraft and trench matériel (Washington D.C.: G.P.O., 1920), 85.
[19] Ibid., 12.
[20] Ibid.
[21] Ibid.
[22] Ibid.
[23] Clarke, World War I Battlefield Artillery Tactics, 8.
[24] McCain, ed., Notes on the French 75-mm. Gun, 12.
[25] Bradley Meyer, “RE: Book recommendation request,” e-mail.
[26] Clarke, World War I Battlefield Artillery Tactics, 8.
[27] Bradley Meyer, “RE: Book recommendation request,” e-mail.
[28] Clarke, World War I Battlefield Artillery Tactics, 8.
[29] Bradley Meyer, “RE: Book recommendation request,” e-mail.
[30] Ibid.
[31] Ibid.
[32] Bradley Meyer, “RE: Book recommendation request,” e-mail.
[33] Robert A. Doughty, The Seeds of Disaster: The Development of French Army Doctrine, 1919-1939, (Mechanicsburg, PA: Stackpole Books, 1985), 102.
The new weapon weighed 1,100 kilograms,[6] and had a maximum range of 6500 m.[7],[8],[9] The 75-mm gun incorporated a barrel that was not welded onto the rest of the gun, a rotary breech,[10] and a revolutionary hydro-pneumatic recoil system. A piston connected from the exterior to the barrel. The firing of the gun pushed the barrel backwards, bringing the connected piston with it. The piston forced a special non-freezing mixture of water and glycerin[11] around a curve, where it pushed a floating piston forwards, which compressed an air chamber. The compressed air acted as a spring, pushing the floating piston back,[12] and, indirectly, the barrel. This prevented the artillery piece from lurching backwards during a recoil, making it safer and more reliable to operate. Its action is illustrated in the image below. In the first image, the gun is at ready. The second image shows the shell (black with a red tip) being fired, causing recoil, which pulls the piston connected to the barrel (red) back, which causes the glycerin-water mixture (orange) to go around a curve, pushing the floating piston (red) forwards, compressing the air (blue). The third image depicts the air (teal) pushing the floating piston back, forcing the glycerin-water mixture back around the curve, forcing the piston back, which pulls the barrel with it. This type of recoil mechanism had not been used in earlier weapons.
[Image pending permission for use]
[13]
The 75 mm. gun had a rotating block[14] with a hole that, when the block had been rotated to the correct position, lined up with the barrel, so that the old shell could be ejected by an automatic mechanism, and the new one inserted.[15] The cylindrical block was edged with gear-like teeth which allowed it to turn easily, and to resist the force of the explosion when the gun was fired.[16] A rotating handle on the block connected with a lanyard that, when pulled and released, would release a hammer to hit the striker in the gun, which would in turn hit the primer, firing the shell.[17]
[Image pending permission for use]
[18]
The gun could fire a wide variety of shells, examples of which are shrapnel and high-explosive shells. The high-explosive shell weighed 5.3 kg,[19] and could be fired to a range of up to 6500 meters.[20] A time-delayed explosion allowed the projectile to penetrate the target before exploding, causing greater damage.[21] In contrast, the shrapnel shell, or “robin” shell, weighed 7.2 kg,[22] and had a range of only 3250 meters.[23] It employed a more complex delay mechanism: when the “robin” shell hit the ground, the impact would ignite a short time-delay fuse, and the shell would bounce upward, exploding at a height of approximately 5 meters. The explosion would release 300 tiny lead balls, each weighing 12 grams,[24] in a cone-shaped pattern.[25] The lead balls could cover an area about 25m wide by 200 m deep, causing 50% casualties to enemies exposed to them.[26] With a rate of fire of about 20 times per minute, the 75-mm gun could bombard the enemy with about 6000 lead balls per minute,[27] each of which could travel along someone’s arm, or enter the ribcage, where it could bounce around, causing internal damage. The variety of shells made the 75-mm gun versatile in diverse situations.
The French Army in World War I, like many armies before it, developed standard techniques called tactics to handle various situations anticipated in the course of the war. One common artillery tactic was to fire five to six shrapnel shells per gun as fast as possible, and then wait for a random time, and then repeat.[28] The shrapnel shell was very effective against troops out in the open, but completely ineffective against troops in trenches.[29] The high-explosive shell was equally ineffective for trench warfare because of its size; troops could sit with their backs to the trench wall, safe from the 75 mm. field gun, or any similar weapon.[30] Other armies had developed similar artillery units: the British had the 18 pounder, and the Germans, the 7.7 cm FK 96 n.A.[31] The 75 mm. gun and other similar weapons encouraged the shift early in WWI to entrenched warfare, a warfighting context which rendered them much less effective.[32] However, the 75-mm. artillery piece would remain the dominant gun for the French Army, even into the Second World War.[33]
Sources
- Clark, Dale. World War I Battlefield Artillery Tactics. Great Britain: Osprey Publishing, 2014.
- Doughty, Robert A. The Seeds of Disaster: The Development of French Army Doctrine, 1919-1939. Mechanicsburg, PA: Stackpole Books, 1985.
- McCain, H. P., ed., Notes on the French 75-mm. Gun. Washington, U.S.A.: U.S. Government Printing Office, 1917. [Note: Reprint of a magazine article from 1915.]
- Meyer, Bradley. “RE: Book recommendation request.” E-mail message to Ender Berberian, November 8, 2017. [Note: Dr. Meyer is Professor of Military History and Dean of Academics at the US Marine Corps School of Advanced Warfighting.]
- Plumier, Bernard. “THE ARTILLERY IN FIRST WORLD WAR.” March 29, 2004. http://www.passioncompassion1418.com/decouvertes/english_fusees_artillerie.html, (accessed Nov 6, 2017).
- United States Army Ordnance Department, Handbook of artillery: including mobile, anti-aircraft and trench matériel. Washington D.C.: G.P.O., 1920.
Footnotes
[1] H. P. McCain, ed., Notes on the French 75-mm. Gun (Washington, U.S.A.: U.S. Government Printing Office, 1917), 5.
[2] Ibid.
[3] Dale Clarke, World War I Battlefield Artillery Tactics (Great Britain: Osprey Publishing, 2014), 7.
[4] Ibid., 8.
[5] Bradley Meyer, “RE: Book recommendation request,” e-mail message to Ender Berberian, November 8, 2017.
[6] McCain, ed., Notes on the French 75-mm. Gun, 12.
[7] When firing a high-explosive (HE) shell.
[8] McCain, ed., Notes on the French 75-mm. Gun, 12.
[9] Clarke, World War I Battlefield Artillery Tactics, 8.
[10] Ibid.
[11] McCain, ed., Notes on the French 75-mm. Gun, 7.
[12] Ibid.
[13] Bernard Plumier, “THE ARTILLERY IN FIRST WORLD WAR,” March 29, 2004, http://www.passioncompassion1418.com/decouvertes/english_fusees_artillerie.html, (accessed Nov 6, 2017).
[14] Clarke, World War I Battlefield Artillery Tactics, 8.
[15] McCain, ed., Notes on the French 75-mm. Gun, 6.
[16] Ibid., 5.
[17] Ibid, 6.
[18] United States Army Ordnance Department, Handbook of artillery: including mobile, anti-aircraft and trench matériel (Washington D.C.: G.P.O., 1920), 85.
[19] Ibid., 12.
[20] Ibid.
[21] Ibid.
[22] Ibid.
[23] Clarke, World War I Battlefield Artillery Tactics, 8.
[24] McCain, ed., Notes on the French 75-mm. Gun, 12.
[25] Bradley Meyer, “RE: Book recommendation request,” e-mail.
[26] Clarke, World War I Battlefield Artillery Tactics, 8.
[27] Bradley Meyer, “RE: Book recommendation request,” e-mail.
[28] Clarke, World War I Battlefield Artillery Tactics, 8.
[29] Bradley Meyer, “RE: Book recommendation request,” e-mail.
[30] Ibid.
[31] Ibid.
[32] Bradley Meyer, “RE: Book recommendation request,” e-mail.
[33] Robert A. Doughty, The Seeds of Disaster: The Development of French Army Doctrine, 1919-1939, (Mechanicsburg, PA: Stackpole Books, 1985), 102.