Machine gun armament of the pillbox

First, let's remember, and perhaps learn for the first time, what a pillbox (a long-term firing point, or more correctly, a structure) is.
Since its birth during the First World War, the pillbox as a concrete structure had already evolved into a a permanent fire structure constructed of reinforced concrete and which is the basis of modern permanent fortification of the area and the main element of modern fortified areas (the authors like this definition from the Soviet fortification dictionary of Shperk, 1946 edition).
Let us remember that the difference between a pillbox and a bunker is primarily that the latter is, in fact, a tree-earth firing point (structure).
That is, a pillbox is a structure that is part of a fortified area, in which a fire system of all available fire weapons is organized, engineering preparation of the terrain with a system of obstacles and barriers, including artificial ones, a communication system, camouflage, etc. Ideally, of course. Historically and in their majority, pillboxes are armed with machine guns, this is logical from the point of view of the fact that initially on the battlefield tanks as such there were none, and after their appearance the task of fighting them became primarily solved artillery, with its subsequent specialization into anti-tank, etc., as technical progress progressed.
However, this is not a dogma, and, of course, some readers will recall many examples of pillboxes with mixed machine gun and artillery armament, for example, the "Maginot Line".


Or the largest structure of our “Karelian fortified area”, the so-called “Stalin line”, the artillery semi-caponier APK-1 “Elephant”, where the two 85-mm guns currently installed were previously preceded by two 76-mm guns, which are complemented by a combat casemate with a heavy machine gun.

Some may recall fully artillery pillboxes, such as the artillery semi-caponiers on the “Stalin Line” with two 76-mm guns on caponier carriages of the 1932 model with spherical armored mantlets.

It should be noted that the share of pillboxes with artillery or machine gun-artillery armament is very small compared to the simply gigantic number of pillboxes with only machine gun armament. And, frankly speaking, pillboxes with mixed armament are also relevant to our story.
Types of machine gun armament of the pillbox by cooling type
Machine gun pillboxes, based on the types of cooling used, are armed not only with water-cooled or air-cooled machine guns, but sometimes with both types of machine guns simultaneously. First, about the first two, and the last case should be examined in more detail.
Since the heyday of the era of building a line of fortifications consisting of pillboxes (as well as individual forts, like the French or Belgians) came in the period between the First and Second World Wars and until the end of the latter, they were armed with those types of machine guns (in terms of their cooling during firing) that were prevalent in the army's arsenal. For example, the French, Czechs, and Dutch at that time used mainly machine guns with air-cooled barrels.

A pair of French MAC M1931 machine guns in a pillbox on the Maginot Line.

Spark Czechoslovakian ZB 53 / Vz.37
And the Dutch, the Finns and our country are with the water spirit.

Austrian Schwarzlose M1907 in a Dutch pillbox

Finnish "Maxim" on a mount similar to that installed in most of the pillboxes of the "Mannerheim Line"

Our "Maxim" on the Gornostaev PS-31 machine tool, typical for the pillboxes of the "Stalin line"
Well, the Germans used both types of machine guns.

MG 08

MG-34
Please note that when using air-cooled machine guns in pillboxes, to ensure sufficient combat rate of fire and fire density without the influence of such situations as, first of all, overheating of the machine gun and the need to change the magazine (yes, the photo from the Maginot Line clearly shows the magazine feed), machine guns are often located in twin mounts. Moreover, the machine gunner was instructed to fire alternately from each machine gun and only at critical moments of the battle - from two simultaneously.
In addition, by installing air-cooled machine guns, both the French and the Czechs were covering their bases and duplicating the firing sectors of neighboring machine gun mounts in one combat casemate almost completely. The French went further than anyone else; in the photo above from the Maginot Line bunker, you can see that with the help of a monorail mounted on the ceiling, it was possible, if necessary, to replace the armor mask with machine guns with an anti-tank gun in an armor mask of a similar size, or replace failed machine guns with spare ones.
Naturally, when installing a machine gun or machine guns with water cooling in a pillbox, the disadvantages associated with overheating become insignificant, albeit at the cost of having to install a tank with a sufficiently large supply of water, a pump (usually manual) for pumping it, and a system of pipelines and hoses. But there are also disadvantages here, first of all, the lack of duplication affects, unlike a pair of machine guns on one carriage, in the event of a long delay in firing or failure of the machine gun. And a lot of water is also needed for cooling, so often in such pillboxes a well is equipped, if not for water suitable for drinking, then at least for collecting drainage water in the machine gun cooling system.

A manual column in the well of one of our pillboxes of the Karelian Fortified Region

A well in a pillbox of the Soviet unfinished "Vidlitsky fortified area"
Options for installing machine gun weapons in bunkers
The above machine guns are mounted, however there is a practice of using light machine guns in pillboxes, naturally, with air-cooled barrels. And there are also several such cases. They differ primarily in that this is either the installation of a light machine gun as the main armament, or as an additional one.
To begin with, we should talk about cases of installing a light machine gun as the main armament of a pillbox, for this we will consider an example of, so to speak, "weakly protected" pillboxes. The term is not entirely scientific, but it gives an idea. Good examples of such pillboxes are our domestic LOT - false firing points and Finnish "fragment-resistant" pillboxes, both of which were built in large quantities.
LOTs are usually located between the main pillboxes of a fortified area and at least partially duplicate their firing sectors. Such structures (ordinary concrete 15-20 cm thick, an embrasure or embrasures for frontal fire) were built primarily to mislead the enemy, when, having approached the LOT and being fired upon from there, he would mistake it for the main pillbox and spend his strength, and most importantly, time, to destroy it. Given the simplicity and cheapness of such a structure, no special mount is provided for firing from it; fire is conducted from an ordinary infantry light machine gun.


As for the Finnish "fragment-resistant" pillboxes, they are a more serious design, made of reinforced concrete. And they even have some kind of mount and a seat of the so-called "bicycle" type. The Finns used their air-cooled "Lahti-Saloranta" L/S-26 light machine guns and Swedish Kg m/21 machine guns - clones of the American BAR. It seems that any light machine gun could be installed in such a mount with minor modifications.


They are literally "splinter-proof" - the corresponding Finnish inscription has been preserved on them.

These Finnish “weakly protected” pillboxes are usually located in the gaps between the main pillboxes of a fortified defensive node and are intended for flanking fire.
As for such structures as reinforced concrete structures, pillboxes made of precast concrete elements, etc., the machine guns in them could be absolutely any.

Now let's move on to the case of using a light machine gun with an air-cooled barrel as an additional armament of a pillbox. Quite often, in addition to heavy machine guns, a light machine gun was included in the machine gun armament of a pillbox, of course, if it was available. It is additional, since it either covers a secondary direction for firing (for example, partially duplicates the firing sector of a neighboring pillbox), or controls the approach to the pillbox from the rear and protects the entrance group. Naturally, in the event of a failure of the heavy machine gun of the main armament of the pillbox, it was assumed that fire would be conducted through its embrasure from a light machine gun. A good example of this use of light machine guns will be the Czechoslovak pillboxes, in which mounts were provided for them in the embrasures.

As for Soviet pillboxes, they usually have an embrasure to protect the entrance. On the diagram it is number 9.

It, in turn, was closed with either a RZ-31 rifle shutter for firing from any hand-held firearm. weapons, including a light machine gun.

Or, instead of it, a special machine gun shutter was installed, for example, PZ-40, in which it was already possible to fix the same light machine gun and fire at enemies approaching from the rear (it was the light machine guns DP-27 or DT-29 that often served as a supplement to the machine gun armament of our pillboxes, consisting of heavy machine guns of the Maxim system).

Modernity and new views on machine gun armament of the bunker
Thus, it can be said that machine guns with both types of cooling found their application in pillboxes, moreover, it happens that in one specific pillbox machine guns of both types are used. However, it should be noted that, let's say, the most "deserved" are machine guns with water-cooled barrels, as the most consistent with the concept of pillboxes and well fulfilling their role in combat conditions, and en masse in hundreds of pillboxes. After all, if we talk about our military stories, it is important to know that they were installed in all the main structures of the "Mannerheim Line" and "Stalin Line". Accordingly, during the battles, water-cooled machine guns proved their high efficiency.
Therefore, even after the Victory in the Great Patriotic War, the surviving pillboxes, the use of which has not lost its relevance (for example, the structures of the "Karelian fortified area"), retained their armament of water-cooled machine guns, only on more advanced mounts and with a more advanced fire control system. And the pillboxes of fortified areas, mainly on the eastern border of our Motherland, were built after 1945. By the way, in some places we are still ready to use them.

Machine gun mount I8-DP, manufactured in 1951
As a lyrical digression, we note that the well-known actor, musician and singer Mikhail Boyarsky served in the army in the 14th separate machine-gun and artillery regiment, right in the “Karelian fortified region”.
The modern concept of a pillbox is completely different, starting with the armored machine gun mount BUK with a crooked-barrel machine gun.


And ending with the universal fire structure "Gorchak", the machine guns in which are now all air-cooled.

Conclusions
It seems that this is far from the end of the development of the DOT with machine gun armament and including machine gun armament, it is just that the human shooter will be replaced by remotely controlled modules and artificial intelligence. After all, technically, it is not a big problem to mount the DUM itself, the robot loader, which will feed and load the machine gun from ready-made belts equipped in factory conditions. The main task is facing the engineers who create the software that controls the entire system, and the AI that recognizes the target in any conditions and carries out guidance.
P.S. The authors express their deep gratitude to their colleagues from the Internet resources “Karelian Fortified Region”, “Environs of Petersburg”, MPC “Sestroretsk Line”, ICC “Stalin Line” and “Military Album” for information and photographs.
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