37mm Mle 1916 Infantry Gun

[David]

The 37mm Infantry Gun was introduced in the French Army during 1916 (and it thus preceeded the introduction of Mortars in that army). It's was mainly meant to be employed against enemy Machine Guns and entrenched positions, using pin-point accurate fire against loop holes etc. The whole Gun could be easily broken down into three packages, that could be carried by soldiers. The packages where: the barrel (40 kilos), the undercarriage (40 kilos) and other parts (28 kilos). It could also be fitted with wheels and pulled by a horse, or manhandled by soldiers, which gave it excellent mobility. If the wheels were removed from the foldable trail, aforward leg could be folded down, thus making a sort of low tripod. It could also be fitted with a small shield.

The gun had a maximum range of 2.400 meters, but the general view was that fire beyond the range of 1.500 meters was pretty pointless. On short ranges it was very accurate. The trajectory of the gun was very flat, however, which meant that it could only be used in direct fire, as it could not shoot over intervening terrain.

Two types of ammunition were used: a massive steel bullet of some 0.56 kilos, and a HE grenade of some 0.45 kilos. The massive steel shot proved less useful, at by the end of the war it was replaced by a HE cast iron shell, filled with black powder. The rate of fire was some 15-20 shells a minute.

The crew of the gun consisted 7 men: a commanding NCO, a gunner, a loader, three ammo-carriers and one driver, for the horse and the caisson that each gun was equipped with. On the caisson 192 shells could be transported, and they came loaded in boxes, each containing 16 shells. The mix of shells were for the most time 50/50.

There was some debate over the real value of the 37mm gun. Both the US Army, and the Austro-Hungarian Army adopted 37mm guns, but at the end of the war the Austrians intended to replace it with a mountain gun, and the Americans eventually dropped it as well. It was, however, used some time by the Palish Army after the war. (The Germans tried 37mm guns, both a design of their own, and captured french pieces, but decided against employing it.)
The calibre of the 37mm gun was by many considered to be too weak. There were doubts in the French army as well. During the most intensive phases of the trench war, mortars proved much more useful, and these light guns were gradually phased out. However, in the final months of the war, when the warfare once turned quite mobile, they again proved to be very useful. Their ammunition was much lighter than most mortar ammunition, and thus more fitting for mobile warfare, and in situations were hastily emerging targets - like a HMG - had to be suppressed, they were much faster in bringing fire on the target than a standard mortar. (Photos below by Michael Casale.)

In a French Tactical Manual from the war, its useage was described thus:
"The tactical properties of the 37mm. cannon are:
- Its mobility, the small space required for ammunition which allows it to follow the infantry in any part of a fight.
- The ease with which it can be hidden behind a parapet, or sunk into the soil in constructing unimportant works; the possibility of delivering a masked fire.
- The great ease with which it is adjusted or regulated. Its great accuracy which allows it to make direct hits upon embrasures up to 1.200 meters; and a useful range of 1.500 meters.
- The rapidity of its fire which for a short “rafale” can attain 20 shots per minute.
Its percussion high explosive shell is used against troops and material, its steel shell against armour. Its effects can be compared to those of a grenade which before bursting could pass through either three rows of sand-bags, or wooden protection, or a steel plate. It has little effect upon earth shelters.
It has been designed to destroy by direct fire any machine gun within sight. It also gives appreciable results against troops taken under an enfilade fire.
Use in offensive engagements. The 37 mm. cannon is a battalion weapon. In certain cases, the colonel can retain the use of it. It is used :
- To prepare and follow up an attack.
- To break any enemy resistance in the course of an assault.
- To cooperate in the occupation of a conquered position.
Preparation and accompanying of the attack.- Before the attack starts, the 37 mm. cannon is installed in an empla­cement whence it can act efficiently, either by: Demolishing machine gun emplacements which might reveal themselves at the last moment; Sweeping those parts which are dangerous for the flanks of the attack; Firing upon the second and third enemy lines. To prevent them being destroyed too soon, it is advisable to put them into action only at the last moment.
Use during an assault. - The 37 mm. gun is taken forward as soon as it is no longer of use in its initial place, or when the infantry needs it to destroy an enemy resistance. Its movement must be foreseen in the plan of engage­ment. The 37 mm. gun is never used in the first waves, because of its vulnerability. It is sufficient that it should follow up the battalion or regimental reserves. It’s used either to destroy a machine gun shelter or to clean up a trench or boyau that it can reach with enfilade fire. As far as possible never use it at too short a distance from its objectives. Cause it to open a masked fire every time it is possible.
Occupation of a conquered position. The 37 mm. gun contributes to maintain the hold upon a conquered position under the same condition as the machine-gun. It is so arranged as to be able to act upon the probable issues of the enemy counter-attacks by seeking an oblique or slanting_' action. It is always advisable to prepare a number of masked emplacements, which supply the means of avoiding easy registering by the enemy's artillery.
Use in defensive engagements. - Endeavor to always place shells into every small window, embrasure, spying post, etc. indicated by the observation service. Prepare numerous emplacements on the front of the battalion and in the rear. During the violent bombardment preceding an enemy assault it is not necessary to keep it in the first line. Ins­talled towards the line of support, or a little to the rear, it might cooperate in the barrage fire especially by enfi­lade fires, It will “sweep” those parts of the terrain where the barrage fire of the artillery will be less efficacious. (very broken up ground, dead angle).
Lastly, the 37 mm. gun can be used for masked fire. It can be registered on the main boyaux, the important cross roads, etc. But the range adjustment must be exa­mined after every fire; for although very accurate, in the^. course of the same fire this gun has important variations­in range according to the atmospheric changes."
- from French Trench Warfare Manual, 1917-18, pages 171-173.
Click on the thumbnails below, for more pictures of this gun:

And click on these thumbnails to see pictures of a surviving 37mm, to be seen in the Brussels Army Museum. (courtesy of Philippe Massin.)

And the photos below show the same gun, taken by yours truly:

Calibre	37mm
Weight of Gun (with shield)	160.5 kilos
Maximum Range	2.4 kilometers
Muzzle Velocity	402 metres per second
Max Elevation	+21 °
Weight of Shell	0.45 kilos (HE)