And Which Was The Top Gun ?
Any comparison of the artillery used by the combatant armies in the Great War is somewhat confounded by one important consideration: all of the armies, except those from the English speaking countries, ranked their guns, howitzers and mortars by the size (diameter) of the rifled bore e.g. 10.4cm. The English-speakers used the weight of the shell propelled, e.g. 13 pounder, as their standard measure for their guns. To complicate matters a little more, the English speakers classified their howitzers and mortars either by the diameter (in inches) of the unrifled barrel or the weight of the projectile in pounds.
The specifically designed trench mortars that were introduced into the British and other armies in 1915, were generally considered to be a weapon of the infantry at the battalion level, and not strictly as 'artillery' in the specialised sense considered here. Inevitably, there was some over-lapping between artillery mortars and trench mortars at the heavier end of the scale. Examples being the French 240mm and 340mm Batignolles, that were widely used by several nations before, and after, the introduction of the mortars specifically designed for trench warfare, and the German Minenwerfer that ranged from 7.6cm to 25.5cm. As a general rule, artillery mortars were considered to be those with a bore diameter in excess of 115mm. There were certain common, and unusual, features in the artillery employed on the Western Front, and it is useful to consider these when making meaningful comparisons.
- All artillery guns and howitzers used by the Great War armies were breech loaded. They were all rifled and had some form of a recoil system - usually a combination of steel springs and hydraulics - to absorb the back thrust of shell as it was fired. It also avoided the need to relay the sights (except marginally) after each firing. The howitzer was developed in the 1600's as a cross between the classic artillery field gun and the siege mortar. The name is derived from the German (haubitze = catapult siege engine) via the Dutch (houwitser).
- The mortars of The Entente Powers were all smooth bored, whilst those of The Central Powers were rifled. Essentially, all except the very large models consisted of a steel tube affixed to a base plate or carriage. At the base of the tube was a firing pin. The mortar shell was dropped into the tube and ejected at high speed by the explosion of an integral explosive device. The recoil was directly transferred to the ground through the base-plate or carriage.
- All guns, howitzers and mortars had to be portable to some degree, so were usually mounted on carriages of various kinds to facilitate their transport. The lighter wheeled pieces were pulled by horses, or a motor tractor, using some form of gun-trail, whilst the really heavy units required railway carriages and railway tracks. Some of the larger howitzers and mortars were actually built into specially constructed firing pits and moved from place to place in pieces on specially laid railway tracks.
- Artillery guns fired higher velocity projectiles and had a relative shallow trajectory (less than 45 degrees). Thus their shells arrived with less warning and were known to the infantry as 'whizz-bangs'. Usually, little evasive action could be taken.
- Artillery howitzers and mortars usually fired heavier projectiles at lower velocities and had steep trajectories (45 degrees, or more). The mortar generally had the more vertical, and faster, trajectory. Accordingly, at least some the howitzer and mortar projectiles could be observed in transit by the soldiers and, on occasion, avoidance contemplated if not always achieved.
- Initially, all the projectiles used in guns, howitzers and mortars were either steel, or cast iron, cases packed with and high explosive (H.E.)* or steel tubes containing an explosive charge and several hundred round metal balls of about one to two centimetres diameter, called shrapnel. (Invented by British General Henry Shrapnel in 1804).
Shell types and characteristics
The H.E. shell gained its effect from both its explosive power and the metal splinters (also often, incorrectly, called shrapnel) that were created by the disintegration of the shell casing. On the other hand, the explosive effect of the shrapnel shell was deliberately far less powerful, and the metal casing acted as a focussing agent forming the balls into a spreading cone directed towards the ground; rather like a shotgun. To be at its most effective, the shrapnel shell had to be exploded in front of the enemy lines (i.e. often over the firer's own territory) with all the potential that offered for 'friendly casualties' from 'collateral damage'. Either type of shell could cause spectacular injuries to the combatants, damage to matériel and disruption to entrenchment systems. Many soldiers were simply blown, or shredded, to pieces by these shells. However, the combined, or individual, effect of H.E. and shrapnel shells on barbed wire defences was much less than at first anticipated. When armoured barbed wire was introduced, later on in the war, the effect was even less: the H.E. shells tended to create large steeply sloped holes into which the barbed wire would settle relatively untouched, making even more formidable obstacles. From 1917 onwards, this 'wire' destruction task was increasingly delegated to mortar teams, with rather more success.
Howitzer and mortar shells filled with shrapnel, having a steeper trajectory, descended almost vertically on the enemy troops. They were, in principle, less likely to inflict 'friendly casualties'.
Classification of guns and projectiles
Artillery guns used on the Western Front were classed into three groups: field (including that accompanying the cavalry and mountain troops), medium and heavy. All the guns had a ratio of length to bore of at least 40:1. Field artillery was used at the Division level backed up with, where necessary, the heavier medium artillery. The heavy guns, being generally less mobile, were at the Corps level.
Howitzers and mortars were usually concentrated into batteries (typically 4, 6 or 8 pieces) and were also normally under Corps command. British guns were formed into batteries of 6 guns but at the times of the great offensives were spread out into gun-lines of hundreds of mixed artillery pieces each with a specially allotted task. Normally spaced at 30-yard intervals, these guns were concentrated to one every 10 yards when the need arose. In the German offensive of spring 1918, guns positioned at 5-yard intervals pounded the areas under attack.
The propellant of the projectile came in various formats. It could be united with the shell to form 'fixed' ammunition (like a 0.303 rifle round) or be 'semi-fixed' and held in a separate container. Generally speaking, the smaller shells were 'fixed' whilst the larger were 'semi-fixed'. In the really large guns the effective range of the gun was, in part, also regulated by the variable quantity of 'semi-fixed' propellant contained in individually labeled bags.
The type of gun also determined the format of the gun carriage: larger guns could not be fully elevated with a closed trail pole and so the 'box' trail was devised to accommodate the 'tail' of the elevated barrel of the gun.
The weight of the various calibre guns, howitzers and mortars varied enormously and this obviously affected their manoeuvrability. The British classified their artillery as 'super heavy' if a gun took a shell of 8 lbs. or more in weight and, if a howitzer or mortar, it had a bore of 9.2 in. or more. The most favoured calibre of heavy howitzer used by the British was the 12 in: the 6 in. served in a more mobile and versatile role. The heaviest British shells, for what were originally the 14in. naval guns mounted on a railway carriage, weighed 1,400 lbs. The French 37cm mortar weighed 30 tonnes of which over 9 tonnes was the gun alone, without its carriage, bed and transporter. Its shell weighed 1,300 lbs.
Range and rapidity of fire
There were two other vital elements which affected the efficacy of artillery on the battlefield: the first was the effective range and the second the rapidity of fire. The effective range was the distance from the gun to a target that could be reliably maintained for as long as the operations demanded. All guns lose accuracy with wear, but, usually, this could be predicted and be subjected to calibration. Equally obvious, is the fact that different types of shells produced different trajectories and ranges when used in the same gun, and these too are often quantifiable for each type of shell. The rapidity of fire was usually related to the size of the projectile: heavy projectiles generally taking longer to manoeuvre and load into the gun. The maximum range of the Great War standard field artillery guns ranged from about 6,000 yards to around 14,000 yards (5,500 to 12,800 metres). Senior artillery officers studied the idiosyncrasies of each gun. And, whilst actively advocating the stream-lining of shells to extend the range, ascertained the variability inherent in different batches of shells and determined the effect of various meteorological factors; all in an attempt to extract the highest possible efficacy from the guns.
The rate of fire with the Great War armies' standard field artillery (7.7 to 10.4cm and 18 to 60 pounder) varied between 2 to 8 shells per minute, with the extraordinary exception of the French 75mm. Model 1897, gun, which was said to attain an astounding 30 shells per minute when pushed very hard indeed. Of course, this rate of fire gobbled up ammunition rations very quickly and, on this account alone, could only be sustained for very short periods.
The heavier field guns (France, 155mm; Germany, 21cm Morser; Great Britain, 6-in.) and howitzers/mortars (Austria, 38cm; France, 370mm; Germany, 42cm; Great Britain, 9.2 in.), though impressive in size and effect, were at their best in the more static areas of the Western Front. But, because of their essential static nature, were highly vulnerable to counter-fire by the more mobile artillery pieces. Their use tended to be restricted to the nighttime. During the day they were usually camouflaged to avoid aerial spotting and directed fire by balloon or aeroplane, and were frequently moved to new locations to avoid counter-fire.
The big guns
Nevertheless, as the war progressed there was a tendency to introduce really large guns and howitzers on the Western Front. Perhaps the best known of these were the three so-called 'Paris Guns' (24cm: being a combination of a 38cm and a 21cm gun firing a 280 lb. shell); so named for the obvious reason that they were especially built by Krupps to shell the city of Paris. They were the longest-range artillery guns of the war, at 80 miles, but were somewhat inaccurate. Contrary to common belief, and many reference books, these were not the famed Krupps' 'Big Bertha'. 'Big Bertha' was a 75 tonne howitzer with a crew of 280 and a bore of 43.2cm that fired at a rate of 10 rounds per hour. They were successfully used to shell the steel-carapaced Belgian forts of Liège and Antwerp and the French fort of Maubeuge. The 'Paris' guns were officially known to the Germans as the 24cm Lange Kanone or, more informally, 'William's Gun'. In three months in early 1918, 367 shells from these guns were fired at Paris. But after the immediate shock, the general psychological effect they generated was limited and the amount of damage inflicted relatively insignificant in terms of the total war effort. (In 1944/5 the 6,200, V1 buzz bombs, [Vergeltungwaffe = Vengeance weapons] with a one tonne warhead, that fell on London and Southern England and the 500, V2 rockets, with a 6 tonne payload, that reached Central London, had largely the same limited effect on the war effort).
The biggest guns used on the Western Front were the French 274mm, and the German 38cm. Great Britain's largest were the re-deployed naval 14-inchers. Howitzers employed by France and Great Britain, respectively, were the 520mm Schneider and the previously mentioned British 12in. The USA used a 14-incher. The French 520mm Schneider howitzer shell, at 3,130 lbs. was the heaviest used in the war.
Manning the guns
The gun team for an ordinary field gun usually consisted of 6 men of whom 3 actually fired the gun whilst the others serviced it. The larger pieces had correspondingly larger gun teams; as mentioned earlier, the German 'Big Bertha' had a crew of 280.
Initially, the principal shell used by all armies on the Western Front was the shrapnel shell. In 1914, the British Army used it exclusively in their field batteries. As the war progressed, the ratio of shrapnel to H.E. changed in all the armies and H.E. became by far the dominant shell. H.E. was also widely used in combination with toxic gas; particularly mustard gas. An estimate has been made that on average it required as many as 1,400 shells to kill one soldier, although other authorities put it as low as 30. Probably, the number fell somewhere in between. In any event, huge amounts of explosive, metal and toxic gas deluged the soil of the Western Front in 4 years of almost constant shelling. Unexploded Great War ordnance is still being collected from the former battlefields more than 80 years after it was fired in anger.
So, which was the top gun on the Western Front, 1914 to 1918? The consensus is that it was the French 75mm. designed in 1897. It was accurate, readily manoeuvrable and had a formidable rate of fire, far exceeding its nearest competitor. Its shell was relatively light - 11.75 lbs. H.E. or 16 lbs. shrapnel - and thus largely ineffective against the German Army's well built dugouts and bunkers. But its high manoeuvrability, excellent range of 9,000 yards and extraordinary rate of fire, allowed it to smash many a critical German assault, or counter-attack, and, literally, save the day for the Allies. Its rate of fire and accuracy when used in creeping barrages was also crucial in the more mobile battles of the latter stages of the war on the Western Front.
*Lyddite (picric acid) was the standard shell-filler in 1914. It was later supplemented and replaced by TNT (trinitrotoluene) which, in turn, was succeeded by Amatol (a compound of TNT and ammonium nitrate).