The Dutch army used many different types of machineguns during the war in May 1940. We shall elaborate on four main types which were in use in the Netherlands itself: the Lewis light machinegun and the heavy machinegun types Schwarzlose, Vickers and Spandau.
The navy and airforce weapons shall not be included.
The Dutch KNIL army [NEI army] also used the Vickers [M.23 6,5 mm], Breda [M.30 7,35 mm], Colt Browning 7,7 mm and 12,7 mm as well as the Johnson Automatic Rifle, the Madsen [M.15 6,5 mm], the Schmeisser MP.28 and the Thompson .45 sub-machinegun. These weapons are also not incorporated in this article.
The standard Dutch light machinegun was the Lewis M.20; the standard Dutch heavy machinegun was the Schwarzlose M.08. The Spandau M.25 was the standard heavy machinegun for the light AA platoons, whereas the Vickers M.18 was kept in service for the reserve machinegun companies. All four these guns are part of our article below.
A historical prelude
In 1884 Harim Maxim developed the first off modern type machinegun. Up to that point the principle of mass-volleys from a single gun-point had come from the Gatling machinegun , which was no more [or less] than an apparatus that produced a rapid fired volley of bullets from a revolving multi-barrel base. This system proved to be a mechanical burden for its operators, because it frequently jammed. Maxim's invention differentiated from the Gatling gun by two main principles: 1) a single barrel and 2) re-usage of the cartridge recoil gasses for automatic reloading.
The Gatling gun had proven itself a very capable and efficient platform for countering mass attacks during conflicts in both North America and Africa. Maxim's invention constituted a leap forward regarding the introduction of efficient infantry weaponry on the battlefield. The introduction of the modern machinegun changed the modern battlefield forever, although Generals in WWI didn't seem to realise that the era of blund massive attacks had been overtaken by the introduction of machineguns on each side.
Although the Gatling gun was introduced in 1862, modern armies only started expanding their arsenals with machineguns in the beginning of the 20th century. Before that, machineguns were still rarities on the battlefield. Remarkably enough, the Dutch military already recognized the imminent need for these weapons in 1900. It would however take them another eight years to present the first of the new generation of weapons to the army. At the eve of WWI the Dutch army had 300 heavy machineguns available. Compared to the German army at that same point this was a modest number. The Germans had no less than 4,900 machineguns available, which was far more than any of their adversaries to be.
The name-addition "light" or "heavy" had no connection with the calibre of the gun [as many people erroneously think] but was in fact connected to the weight of the weapon-platform. In 1914 a machinegun was simply a machinegun; due to the omission of a light version, the addition "heavy" was not used at all. It was during WWI that both the light- and sub-machineguns were developed, and as such name-additions like "light", "heavy" and "sub" were born.
The distinction between a light and a heavy machinegun was made by the following argument in particular: a heavy machinegun was heavy to move, transported by two or three men and usually not operational during transit, whilst the light machinegun was a weapon that could be transported by a single man and be operated immediately by one man too. In other words: the heavy machinegun was designated for static warfare, whereas the light machinegun was a weapon that could contribute to dynamic warfare.
The 1934 German Spandau MG.34 was a perfect example of how to explain the distinction between a light and heavy machinegun. With a heavy tripod [Lafette] with amplified vision-device the MG.34 was designated as a heavy machinegun, without the tripod and simply applied on an integrated two-leg stand it was designated as a light machinegun.
Besides the primary character of simply the weight of the weapon, there is a further connection between that same weight and accuracy. The heavier - or firmer - the undercarriage or base on which a machinegun is placed, the more accurate the produced fire will lay. This aspect is related to the steadiness of the platform [that supports the gun-aiming] rather than the changing characteristics of the weapon itself. Obviously the firmness of the fire-basis does not modify the gun itself, but determines the deviation of the projectile path due to more or less room for "gun hopping" or recoil effect. It is clear that a machinegun operated on a basic spread in the field has more room to hop out of position than a machinegun operated on a 20-30 kg heavy base or [for example] an armoured vehicle.
Another distinction between a light and heavy machinegun was later introduced. This had to do with the designation of the weapons. A heavy machinegun was supposed to be able of producing long sustaining volleys preferrably over long(er) distances, whereas the light machinegun was dedicated to the task of direct fire-support by means of short bursts of covering or suppressing fire. Gradually the heavy machinegun grew into a more robust weapon [e.g. the Colt Browning 12,7 mm] whereas the lighter machineguns lost weight [Brengun]. This development is basically vanished nowadays, where metallurgic developments have facilitated the possibility to produce lighter weapons that are able to sustain heavy duties.
Interchangeability of barrels is a feature that these days can be done in no time. The Germans introduced this feature already with their MG.34, which in all aspects was a weapon that was way ahead of its time in respect of fire rate achievements, sustainability, low-maintenance and interchangeability.
The first light machinegun was designed and manufactured by the American Colonel Isaac Newton Lewis in 1914. This weapon had a battle-ready weight of about 14 kg, which was about one-third or half the weight of the main machineguns in use on the battlefield up to that point. This weapon was introduced during WWI and proved an improvement in the arsenal of the average infantry unit, although it was also clear that drastic improvement of the loading mechanism and weight would be required to make it a reliable and easy-to-handle gun.
The last of the family members that was introduced was the sub-machinegun. The Germans were the first to come up with this type of weapon during WWI, when the Bergmann MP.18 was first seen among storm-troopers. This very easy-to-operate weapon proved to be a sensation, for it was able to match the fire-rate of the heavy machineguns, but it was light to transport and easy to fire on the move. In combination with handgrenades, flame-throwers and good training, the WWI storm-trooper and his sub-machinegun proved to be a battlefield item that represented modern warfare. Yet in 1939 and 1940, the German infantry-men would be able to outmatch their opponents with the availability of modern sub-machineguns like the MP.38 and MP.40 in their lines. The Allied forces lacked any sub-machineguns whatsoever. It again proved that the Germans had learnt the lessons of WWI [power of the airplane, tank and machinegun] much better than their former conquerors.
In the year 1900 the Dutch installed a commission that was instructed to study the procurement of machineguns for the Dutch army. The commission had a great variety of extensive tests performed with a number of available machineguns. In the end the most cost effective weapon was selected: the Austrian made Schwarzlose machinegun with a piece-price of only 1,500 Dutch guilders in those days. The German Spandau M.08 - direct spin-off of the Maxim principle - was twice that price.
The Schwarzlose was designed by the German Andreas Schwarzlose. The weapon was manufactured by the "Oesterreichische Waffenfabrik Gesellschaft" in Steyr [Austria]. In 1906 four machineguns were extensively tested in follow-up trials. The model OWS 1907 - also the standard machinegun for the Austrian-Hungarian army during WWI - was presented shortly hereafter. In 1908 the Dutch Ministry of Defence concurred of the purchase of the Schwarlose machinegun for the Dutch army. It is generally accepted that money must have persuaded the Ministry, for performance-wise the Schwarzlose underperformed in comparison with both the Spandau and the Vickers gun.
The Schwarzlose factory claimed that the weapon could easily produce a fire-rate of 520-550 rounds a minute, but the trials proved these claims false. The actual measured rate of fire was determined at 400-450 rounds a minute, which was considerably less than the Maxim based designs of Spandau and Vickers. This lower fire-rate would mean that in comparison to the other available machineguns, an average Schwarzlose volley would have about 20% less density. The only advantage of the Schwarzlose over the Spandau and Vickers was the low wear of the barrel, obviously partially a positive side effect of the lower firing rate. The Vickers barrel had proven unreliable after 10,000 rounds, the Spandau after 15,000 rounds - but the Schwarzlose barrel only had to be replaced after no less than 29,000 rounds. This was both an operational and an economical advantage.
The Dutch designated the weapon Schwarzlose M.08, where the extension represented the year of introduction. The machineguns had been ordered with a calibre identical to the standard Dutch rifle, the M.95, with calibre 6,5 mm that was also produced in Steyr. The military purchasers thought that this standardization would contribute to better and easier logistics, which in itself seemed a fair consideration. During WWI the Austrians were unable to uphold a steady production for export, which resulted in Dutch initiatives to produce both the machinegun and the rifle locally. Licences were obtained from Austria and soon the Dutch were able to produce their own infantry weapons at the Artillerie Inrichtingen [AI] factory. As off 1915 the vast majority of the weapons were produced in The Netherlands. Between 1915 and 1940 the AI would produce about 2,000 machineguns [on top of the 300 delivered from Steyr].
Meanwhile the Dutch experience with the M.95 rifle in calibre 6,5 mm had proven that the stopping power of the bullet left much to be desired. The Dutch fought numerous local conflicts in the Netherlands East Indies [NEI], and as such some degree of battle experience was gathered. As a consequence of sustained complaints from field-commanders about the insufficient stopping power of the bullets, a commission was installed to review this matter. The commission took plenty of time to conclude that the 6,5 mm rounded full metal jacket bullet indeed lacked sufficient stopping power, especially at short distance. Remarkably enough this outcome only resulted in an instruction to enlarge the calibre of the heavy machineguns, but both the light machineguns and the rifles would continue to be produced in the original calibre. It was decided  that all heavy machineguns would be produced in the calibre 7.9 mm, and that the existing arsenal would be modified to that standard. Probably this decision - although not documented - was supported by financial rather than operational arguments.
The heavy machineguns were organised in companies. Basically each company counted four sections with three guns each or [auxilary army] four sections with two machineguns.
The Schwarzlose machinegun was usually transported on a tailor made cart. This cart was prepared with a gun-standard and provided also room for ammunition and maintenance gear. Initially these carts were towed by a dog-span, which lasted until a few years after WWI. During the interbellum these carts were either pulled by a motor-bike [hussars] or the gun crews themselves. Also horse traction was used.
One gun assembly comprised the heavy gun itself, an even heavier tripod undercarriage and [sometimes] an optical aiming device; altogether a weight of about 40 kg a piece. Obviously the heavy machinegun companies were unwieldy units that were unfit for dynamic warfare. This status would not change or improve before 10 May 1940.
The gun was equipped with a 4.5 litre cooling tube around the barrel and was connected to a drain bucket. This drain bucket was actually a precipitation device. The steam from the heated cooling water found its way through the hose where the steam would transform back into water again. The cooled down water could later be transferred back into the cooling tube, but obviously a certain degree was lost previously. Casemates that were especially designated for use of a heavy machinegun were therefore often equipped with a water drain-pipe that transported rain-water from the roof of the casemate into the interior. Obviously field-units lacked such a facility. It was therefore imperative that additional water was available in large quantities.
The undercarriage basically comprised three major parts: the heavy tripods with scoops at every single leg and an axis-base for the gun-rest, a seat for the gunner and a 180 degrees greased iron ring on which the gun-bed could be slighted from left to right. The position of the gunner was such that the integrated gun aiming device was completely worthless. The gun had to be adjusted in a fixed angle, and as such the gunner would only determine the traverse angle. Later a modern aiming device was introduced that could be connected next to the gun. This amplified optical aid was a product of Carl Zeiss Jena. The device amplified the target twice and was used by the gun-second. As such the gunner could adjust the fixed angles according to the directions advised by his second. A machinegun section was equipped with a larger amplifier [stereoscope] that could give directions and distance of targets to the whole platoon.
The Schwarzlose machinegun was the standard machinegun of the army for field and casemate duties. It was also available for AA duty, and for this a special extendable tripod was available. This device could be expanded in height and was fitted with two slings in which the gunner could rest during operation. A special AA vizier was also available.
In May 1940 the Schwarzlose machinegun was quite outdated. Still the machineguns proved to be highly reliable and robust. The number of break-downs was extremely low. This unexpected positive feature of the Schwarzlose may very well have been boosted by the fact that the Dutch military had hardly had any budget for frequent exercises during the interbellum. Although this poor training resulted in an ill prepared army, it did prevent considerable wear and tear of the weapons. A hidden advantage of a poor situation!
Surprisingly enough the weapons also proved to be able to coop with low maintenance and quite heavy operational circumstances. Quite a number of funny anecdotes are registered about the inventiveness of MG-crews during the war. Lack of cooling water was relieved by urinating over the gun, and mucus proved to be an efficient lubricant by absence of genuine gun-grease. Two huge disadvantages were the sheer weight of the weapon and under-carriage, as well as the low firing rate. Still, the Schwarzlose machinegun was a capable weapon that - certainly in comparison to the Lewis M.20 light machinegun - was generally accepted as reliable and capable for its duties.
Specifications Schwarzlose M.08
|Manufacturer:||Österreichische Waffenfabrik Gesellschaft (in Steyr)
Artillerie Inrichtingen / Hembrug (as off 1915 in licence)
|Firing rate:||400 - 450 r/m (Factory claim: 520 r/m)|
|Gun feed:||215 rounds in a cotton belt|
|Weight:||24,50 kg. (without cooling water)
29,00 kg. (incl cooling water)
44,00 kg. (incl cooling water and tripod)
7,50 kg. (belt with 215 rounds - excl. box)
|Range:||3.500 meter at 30 degree angle|
|Aiming devices:||Angle adjustable vizier
2x amplified Zeiss optical scope
|Remark:||Standard MG Dutch army
2,300 machineguns Schwarzlose available at 10 May 1940
In December 1918 about 1,000 Vickers machineguns with calibre .303 inch [7,7 mm] Mk.1 had been purchased from the British War Office. About 200 of these machineguns were modified for use with the airforce. The guns were designated Vickers M.18 [M.18 no.1 for the 7,7 mm version, and M.18.no.2 for the 7,9 mm version].
The Vickers was a 1912 model that was - like the German Spandau M.08 - based on the Maxim principle. The gun was fed by a 250 round cotton belt. In comparison to both the Schwarzlose and the Spandau, the Vickers was a light weapon. It was about 30% lighter and as such easier to handle. The cooling tube around the barrel was relatively more effective due to the rib-structure [which increased the relative surface] and in order to cool the barrel effectively only 3 litres of water were needed. This resulted in quite a weight profit. The cooling system was - unlike the Schwarzlose - provided with a closed recovery system. As such no cooling water was lost. Only extensive sustained operation made it necessary to replace the cooling water.
The manufacturer claimed a fire-rate of about 550 rounds per minute, but in practise this figure was hard to match. Tests showed that 500-520 rpm was more realistic. Definite weak point of this weapon was the progressive barrel wear; after 40 belts [250 rounds each] the barrel had to be replaced.
The Vickers machineguns were dedicated as the prime machineguns for reserve machinegun companies in the higher mobilisation units. The Dutch army was built around 48 Infantry Regiments. The first 24 regiments were the basis of the army, and contained the standing army units and the youngest reserve batches. The highest 24 regiments contained the older reserve batches and the heavy machinegun companies of these regiments were often equipped with the Vickers machineguns. As a consequence the majority of these machineguns were stored in the arsenals during the interbellum. The coastal artillery command had received about 80 Vickers for AA support.
As off 1935 almost all Vickers were incorporated in a program of modifying all heavy machineguns to the calibre of 7,92 mm. This decision was still a result of the 1925 study of the committee that had investigated the stopping power of the 6,5 mm bullet. Although the 7,7 mm bullet of the Vickers in itself did not lack this stopping power, it was still desired to ream the barrels to 7,9 mm in order to be able to limit the logistic challenge to three calibres: 9 mm for the pistols, 6,5 mm for the rifles and light machineguns and 7,9 mm for all heavy machineguns. When the modification would be finalized the Vickers would be equipped with the 215 round belt transporting the standard 7,9 mm x 57 mm rimmed bullet. The modification was however not completely finished when the German invasion occurred, and as such some units were still facing the enemy with the 7,7 mm Vickers.
The Vickers machinegun was usually fitted on a tripod undercarriage like the Schwarzlose. For these machineguns were no dedicated optical devices available. Sometimes even the stereoscope for the section-observer was left out of the organisation.
The Vickers M.18 was mainly used by the reserve heavy machinegun companies, a few older airforce planes and some armoured carriers [Vickers Carden-Lloyd]. The machineguns were generally appreciated as reliable weapons during the May war. Very few malfunctions were reported.
The Vickers heavy machinegun was used in the British army up to 1968. This in itself is a proof that the concept of this weapon continued to pay off until well after WWII.
Specifications Vickers M.18
|Type:||MG Vickers .303" Mk.1, Dutch designation M.18 no.1 or no.2|
|Calibre:||7.7 mm (.303 inch) [M.18 No.01]
7.92 x 54R mm M.18 [No.02]
|Firing rate:||500-520 r/m|
|Gun feed:||215 round 7.92 mm / 250 round 7,7 mm - both cotton belt|
|Length:||1092 mm (front to rear)
722 mm (barrel)
1500 mm (weapon plus extended tripod)
|Weight:||14,97 kg (without coolant)
18,14 kg (with coolant)
23,13 kg (with basic spread)
30,00 kg (approx. with M.08 tripod)
10,00 kg (ammo box with 250 7,7 mm rounds)
|Aiming devices:||350 m - 2,600 m angle adjustable vizier
No optical aids in NL
|Remark:||Barrel replacement after 10,000 rounds
Approx. 400 guns available in May 1940
In use with higher reserve units
The Spandau M.08 [Dutch designation M.25] is the world-record holder "battlefield butchering". No weapon in the world killed more people on any battlefield than this formidable machinegun. The Entente forces nicknamed the Spandau "the Devil's Paintbrush".
The Germans were the first to recognize the meaning of the machinegun on the modern battlefield. At the eve of battle in 1914 they had no less than 4,900 heavy machineguns available, of which the far majority of the type Spandau M.08. German gun-crews were selected from the best military personnel available and exceptionally well trained. This was a consequence of German vision about the tactical envelop that the machinegun could fill in on the battlefield. Their appliance of the weapon was not only massive, but the way they operated the weapon showed vision and careful planning. They had realised that machineguns - once positioned in an overlapping position - could seal of dedicated perimeters of the battlefield. These techniques would still have to be developed amongst the Entente troops at the cost of huge losses. When the Americans entered the war in the last year, again the price of lacking experience was paid against the German machinegun fire.
The Dutch got hold of the first German Spandau M.08 when retreating German forces requested crossing over the Dutch southern borders at the end of WWI. Save passage was granted provided the weapons were handed over to the Dutch. These confiscated weapons were later compensated to the German government - like any well behaving neutral country would have done. Also, additional numbers of weapons were procured from surplus stocks that were found all over Europe after WWI.
The Spandau machinegun was clearly a direct spin-off of the Maxim principle. The weapon was first produced in 1901. After some modifications the 1908 model would be selected for the backbone of the German army machinegun squads. It was basically produced in two versions. The basic version was designated the Spandau Maxim LMG 08, and the version with a pistol-like grip was designated LMG 08/15. The weapon was mainly produced by the Deutschen Waffen und Munition Fabrik GmbH in Berlin, Germany. In total this factory and its subsidiaries would produce over 100,000 machineguns during WWI.
The captured Spandau's were first stored in the arsenals of the Dutch army. As off the year 1925 they were officially introduced in the army when numerous AA platoons were formed. The field army never made use of the weapon. The heavy machineguns from this type were designated Spandau M.25 and assigned to virtually all AA machinegun platoons and as a support weapon for the heavier AA units. In the end about 480 would serve in AA units as support against low flying planes.
Although the quality of the machinegun [out of production] was regarded very high, the second hand products that had been confiscated by the Dutch in 1918 often proved totally worn-out. There are reports from a number of AA units [usually comprising four MG's each] that none of the machineguns were operable when orders to open fire were received at the morning of May 10, 1940. The Spandau machineguns generally proved quite worthless. Their extremely poor performance caused many gaps to fall in the low altitude air defences of the Dutch in May 1940.
Specifications Spandau M.25
|Manufacturer:||Design: Spandau (Berlijn),
production: DWM (Deutsch Waffen und Munition Fabrik GmbH)
|Type:||Spandau M/08 (M08/15 pistol grip) - Dutch designation: M.25|
|Firing rate:||450-500 r/m|
|Muzzle velocity:||920 m/sec|
|Gun feed:||250 rounds 7,92 mm shackle belt|
|Length:||1092 mm (front to rear)
720 mm (barrel)
|Weight:||19,00 kg (without coolant)
22,13 kg (with coolant)
34,05 kg (with undercarriage)
7,26 kg (250 round shackle belt - excl. box)
|Max range:||4.000 meter at 32 degree angle|
|Aiming devices:||0 m - 2,000 m angle adjustable vizier
2.5x Zeiss optical telescope ZF12
|Remark:||Majority of weapons were worn-out in May 1940
700-800 guns in use in May 1940, of which 500 in AA platoons
The Lewis light machinegun was briefly addressed hereabove when we spoke of the development of this weapon during WWI. The American Colonel Lewis - former coastal artillery commander in the American army - managed to modify patents of Samuel McClean to such a result that in 1912 a prototype light machinegun was born. This weapon was the first machinegun to be fired from an airplane. Although demonstrations with the weapon were successful, the American army showed no interest to procure any of Lewis' products at that time.
When WWI had broken out Lewis realised that his clients would most likely be found in blazing Europe, and so he moved to Belgium. He founded a company named "Armes Automatique Lewis". His design was well accepted by the British in particular, and many orders followed. England, France, Belgium, Canada and the United States soon showed their interest after the first battle-field results proved promising.
The Dutch introduced the Lewis light machinegun only in 1920, and designated it as the machinegun M.20. The airforce and the cavalry developed their own versions in calibre 7,92 mm, whereas the army maintained the standard of 6,5 mm.
Although experience with the machinegun on the battlefields of WWI had presented the soldiers in the field with quite an array of problems, the Dutch made the M.20 the standard light machinegun of the army. The problems which would never be solved were the relatively heavy weight [12 kg unloaded], the mechanical problems with the round magazine and subsequent bullet transport and the extreme vulnerability to dirt and shock.
The round magazine was designed by the Dutch industry. The standard type contained 47 rounds [7,7 mm] and was based on a British design. The Dutch required a larger magazine, and the Artillerie Inrichtingen constructed the standard magazine for 97 rounds of 6,5 x 53,5R bullets. The problems with the magazine occurred in particular when the gun was transported with the magazine fitted on the weapon. When operated directly after or during transit, nine out of ten times the first bullet jammed. The jammed bullet was only recoverable with a special tool, which was not a desirable feature when being under fire! Obviously this was a huge disadvantage for a weapon that was designed for dynamic infantry combat.
The weapon was quite reliable when operated in a fixed position. The fire-rate was accurate for a light machinegun, but intensive use quickly decreased the reliability of the mechanism. The entire loading and firing mechanism proved extremely fragile when the operation of the machinegun caused the metal temperature to rise. The slightest expansion of parts caused the weapon to hamper or jam.
Prior to war break-out the Dutch were studying on replacement of the M.20 and the British Brengun was reviewed amongst others. It all came too late to alter the score. At 10 May 1940 the Dutch army had to coop with all the disadvantages of the M.20 Lewis. The army had no more than 8,000 of these MG's available. That was about half the desired and required quantity.
First line troops had about one M.20 for every fifteen men, which was a low quantity considering that also heavy machineguns and mortars were available in low numbers. Bearing in mind that the Dutch soldier was equipped with a bolt-action rifle it is needless to say that the fire power of a Dutch infantry section was quite modest.
Specifications Lewis M.20
|Manufacturer:||Design: Isaac Newton Lewis (USA),
production: AAL (Belgium) and Artillery Inrichtingen [Netherlands]
|Type:||Lewis, Dutch designation: Light machinegun M.25|
|Calibre:||6,5 mm [army] 7,9 mm [airforce]|
|Firing rate:||450 r/m|
|Gun feed:||97 rounds 6,5 mm x 53,3R - magazine|
|Weight:||12,00 kg (without magazine)|
|Max range:||1.500 meter|
|Aiming devices:||Fixed vizier|
|Remark:||Poor dynamic quality
8,000 machineguns in use in May 1940
Viziers and optical devices
There is a lot of confusion amongst non-military people about the operation of machineguns. People tend to think that firing a machinegun is like aiming a shower-head: all that is aimed for gets wet. This is a wide spread misunderstanding! Operating a machinegun successfully beyond a few hundred yards requires excellent training and skills. Besides basic aiming at the target many more features and factors pop around the corner.
The first misunderstanding is the one we already briefly addressed. People think that aiming a machinegun is just locking your target in the vizier and pulling the trigger. Well, at 300 yards a person is no more than a dot in your vizier, and successfully targeting a dot can be quite a challenge!
A second misunderstanding is the general perception that a bullet travels in a straight line from barrel to target. Depending on the type of ammunition, bullets tend to follow a trajectory in a (ver)sine shape. Besides the pure ballistic-features, factors like humidity, wind and/or temperature play a role, especially if one [or more] of these factors grow to extremes. Another factor that matters considerably is the wear-ratio of the barrel. The more bullets have been fired, the more considerable the wear - especially when the fire-operation was very intensive or in the shape of extended volleys. The more intensive the operation within a brief period of time, the softer the metal of the barrel becomes from the rising temperature. This dramatically increased the wear of the barrel, and resulted in decreasing muzzle velocity as well as barrel deformation.
In order to overcome all these challenges the gun aimer has a number of counter measures. First of all thorough training; practise shapes the master. Secondly machineguns had to be produced under firm specifications. Extensive calibration-trials were performed to calibrate the gun performance. As such armies were able to produce tables and nomograms that provided the gunner with information about pre-setting the angle adjustable vizier according the factors that mattered [like heavy cross wind or wear-ratio after 10,000 bullets fired]. Thirdly, gunners were instructed to produce short bursts of fire. That works two ways. One maintains a better aim and one saves ammo and barrel.
Viziers on machineguns were usually produced in the form of adjustable angle settings that could be adjusted in regular steps. The majority of heavy machineguns were able to produce long distance fire up to 2,500-3,000 metres, which would tilt the angle to the maximum setting of (usually) 25-30 degrees positive. This setting would obviously result in a rather steep curved trajectory. The gun-direction was also often adjusted by a setting-device that was mounted under the bottom of the chamber. This device was connected to the slider that moved over the horizontal ring that was mounted on the tripod. Obviously not all undercarriages were fitted with a sliding ring, but in the Dutch army these devices were standard.
It is however clear that during intensive battle-field conditions hardly anybody would be able to calibrate its viziers to the factors applicable at a certain time. Experience and training were the most important factors to adjust the aiming point during combat. Also other means of assistance to the gun crews were quite common. Especially in defence situations, where positions and trenches were prepared well ahead of the enemy's arrival, crews were able to measure-in landmarks and trees from their machinegun position. Sometimes they even marked trees, poles or houses so that the distance between the gun and a particular landmark was known or visible by clear markings. Any target close to such a landmark could be "measured" by making use of these markings. In the Dutch army in May 1940 this method was often used.
In the dynamic theatre measurement preparation can usually not be taken and as such one is dependant on experience or other aids. During the late thirties two types of aiming aids were introduced in the Dutch army.
First of all, the stereoscope. This device was also in use with both the land- and sea-artillery. It was a tube with a certain length [width] with a scale projected on the sight-glass. The length of the tube was an extension of the human vision. By looking through the sight-glass one could compare the target to the scale and determine the distance. The wider the tube-base [up to six or seven metres for heavy navy- or coastal artillery], the more accurate the measurement. The tube-base that was used for the machinegun companies was no more than 70 cm, but this was accurate enough for this short distance. This stereoscope was available to the company or section commanders and usually operated by a sergeant-observer or a lieutenant-observer. In many units however no stereoscope was available whatsoever.
The other optical device that was introduced before the war was an optical amplified aid that could be mounted next to the machinegun. The Dutch used either a two-times or two-and-a-half-times amplifier device from Carl Zeiss Jena. These aiming aids were considered impressive improvements for mediocre range fire.
Basic machinegun tactics
The Dutch had a shortage of machineguns in May 1940. The availability of about 11,000 machineguns [8,000 M.20 light MG's; 2,300 M.08 heavy MG's and 700 M.18 heavy MG's] was far too less to cover all front-sections adequately. Yet - at the heavier defended positions such as the Grebbeline, quite dense concentrations could be found.
During WWI the belligerent parties soon learnt the hard lessons of the battlefield. Without teaching a full lesson in battlefield tactics, a number of basic rules for machinegun appliance on the battlefield are interesting enough to share with the reader.
The first basic rule of machinegun warfare is the absolute desire to be able of producing overlapping fire. This desire does however require at least two machineguns, but preferably three. An isolated position with just one machinegun is easy to overcome by an enemy once this position defends open terrain. An enemy that operates in two teams coming from two directions can easily outflank such a position and overtake the gun or destroy it. A position with two machineguns is a lot less easy to overcome, for it can cover both angles of the approach zone. If two machineguns are available it's generally preferred to build two single MG-point relatively close to each other. The vulnerability of two positions is considerably less than a concentration of two guns in a single position.
If one bears in mind that two single positions close to each other is a basic minimum to defend a small perimeter, one can easily understand that a local defence-commander would prefer a certain redundancy in his gun-position. That redundancy is created by applying three guns in a narrow section of which the middle one is able to cover both the left and the right extremity of the field of fire of the outside-guns. This way all three machineguns are able to produce such a deadly cone of fire within the total perimeter that it is hardly pregnable to any assaulting party. Should one of the machineguns fail or be destroyed the remaining two can still continue to spray the whole perimeter. It will take an enemy a great deal of effort to penetrate such a well covered zone.
Machinegun positions are preferable constructed at such a location that they are able to seal off certain perimeters or landmarks. If defences can profit from elevated positions this usually proves advantageous for infantry positions and posing the enemy with the challenge to climb the defended slope. For machinegun positions it is not at all an advantage to fire from elevated positions, unless just a narrow approach is defended. The depth effect of the fire gets lost due to the fact that any volley will bash the ground around the aiming point. The sealing-off of a perimeter is therefore hardly possible. Machinegun positions are usually the most effective at 0-level. This way volleys will seal off an entire box with large depth. The Dutch landscape provided for such effects for the majority of the country is as flat as a pancake.
In the Grebbeline - which is partially built on a product of the last Ice-age - the southern sector of the defence line was constructed on elevated ground [Grebbeberg hill]. The Achilles heel of the defences around the hill lay just east of the small stream called Grift. The main defence-line had been given shape on the east side of this small river, partially on the western slope of the hill [up to 55 metre height difference]. The Dutch had however failed to construct machinegun casemates on 0-level east of the hill, with exception of one isolated point. The four main heavy machineguns positions that were able to spray the approach zone had been constructed on top of the hill. This way these fire-points were unable to produce sufficient in depth fire [or at the foot of the hill] and as a consequence the German assault parties relatively easy negotiated these four points of defence. It was a clear show of poor planning and lack of experience.
The Dutch machinegun company
A regiment of infantry comprised three infantry battalions [700-800 men each] and a heavy machinegun company [150-180 men each]. Every infantry battalion comprised three infantry companies and one heavy machinegun company. Also the Army Corps had one or two independent heavy machinegun companies. All these companies were more or less equipped and manned in the same manner.
Usually a heavy machinegun company [designated "MC"] comprised four sections [35-40 men each] with three machineguns [8-10 men per gun].
An MC was commanded by a Captain or 1st Lieutenant. The sections were usually commanded by a Lieutenant or senior NCO. The eldest section-commander was the executive MC Commander. The MC Commander usually had a signal- and messenger-party, a sergeant-observer and one or two other aids at his disposal. The MC's had no independent staff.
Each machinegun had an 8-10 men crew, a Corporal [vice gun commander] and a sergeant [commander]. The eldest gun-crew commander was usually the executive section commander. The large crew was necessary to transport the gun, to look after ammunition transport during combat and to be able to replace casualties. The actual operation of the gun was usually performed by two or three men.