The field gun that was to become the 18pdr owed its origins to the Second Boer War. That distant and muddled conflict emphatically pushed home the point to the denizens of Horse Guards and Woolwich, that the state of the British Army’s field artillery had become more than a trifle parlous. The early days of the Boer War showed that the Boers could outrange and outshoot anything the Artillery could put into the field. The only immediate short-term solution was for the British Artillery to order (secretly) 108 Erhardt 15pdr guns directly from Germany, but once these guns were delivered, the Boer War had settled down into a prolonged and nasty guerilla campaign with little artillery content. But the experience gained with the 15pdr Erhardt guns gave many pointers as to what the Royal Artillery wanted for their field pieces. The Erhardt guns were sound enough but insufficiently robust for the prolonged rigours of British Army service, and almost as soon as they were delivered the search for a long term replacement was under way.
The task for this long term programme was given to General Sir Henry Brackenbury, and so thorough and far-ranging were his initial investigations that he ordered that all the field artillery in service with the British Army would have to be replaced within a three year period – in fact it was he who started the initial programme by ordering the Erhardt 15pdrs. Brackenbury issued fairly stringent requirements to British industry and among his required equipments were guns for the field and horse batteries. In time the two guns emerged as pieces firing 13.5lb or 18.5lb projectiles, but of the three main producers (Vickers, the Royal Ordnance Factories and Armstrong) there was no overall product that emerged as a clear choice.
The answer was, in both cases, to amalgamate the designs and see what the end results looked like. Thus, with both the 13.5pdr and the 18.5pdr guns, the barrels were from Armstrong, the cradle and some of the carriage came from Vickers, and the bulk of the carriage was a design from the Royal Arsenal at Woolwich. For their day, both designs were thoroughly modern and sound, but almost as soon as the results were issued, voices were raised as to whether or not two almost similar guns were what the Army needed – the difference between a 13.5lb and a 18.5lb projectile hardly seemed to be worth all the extra efforts involved. During the early 1900s, there was a great deal of discussion and debate as to the merits and demerits of both types of gun, but in the end the contest was settled by a political decision made by the Prime Minister of the day, Arthur Balfour. He produced a compromise. As the initial call was for guns for both the horse and field batteries, the smaller gun would go to the Royal Horse Artillery and the larger gun to the Royal Artillery field batteries.
Picture 1: Against the mud
Thus the 18pdr gun became the 18 pdr OF Gun, and it was accepted for service on June 30 1904. Soon after, other empire and Commonwealth governments followed suit and the 18pdr became a Commonwealth gun. The Indian Army also decided to adopt the 18pdr to the extent of setting up their own production line – by 1914, 99 18pdrs had been made. In the United Kingdom the 18pdr was soon in production and by the outbreak of the Great War in 1914, some 1126 equipments had been produced. Of these, 280 had been sent to Australia, New Zealand, South Africa and Canada (where the first arrived during 1906).
The first 18pdr has wire-wound barrels with a calibre of 83.8mm. As early as 1906 the barrel design was changed to the more modern convention of inserting the inner tube liner into the gun sleeve – this enabled worn barrels to be relatively easily re-lined, a fact that was to be of great advantage between 1914 and 1918. The wire–wound barrels were the Mark 1 and the later barrels the Mark 2 (or Mark II at the time – this article will use the later arabic where possible). To add to the variety of early Marks, worn Mark 1 barrels were converted to mark 2 standard, when they became the Mark 1 *. The gun used a hydro–spring recoil mechanism and a single–action interrupted–screw breech. The carriage used a single pole trail which, on the move, was hitched to a limber carrying 24 rounds of ammunition. The gun and limber were towed by six or eight horses, while more horse teams towed extra ammunition waggons. As with the gun, the carriage underwent some modifications (there was even a Mark 1 **), but the main change came after experience in action. Once the Great War had settled into a prolonged artillery action, it soon became apparent that the recuperator springs used were incapable of standing up to the strains of long term warfare and many broke in action. During 1915, a new recuperator design with a hydro–pneumatic system was gradually evolved for retro-fitting to all guns in the field and on the production lines. On the lines a lengthened cradle slide was introduced for greater stability when fired and these two innovations then changed the carriage to the Mark 2.
Picture 2: British 18 pounder field gun and crew
Once that was done the 18pdr proved to be a sturdy and reliable workhorse and by the end of 1918, 8,393 had been produced in the United Kingdom. Even this prodigious total was insufficient to meet the demands of an ever-growing Allied Army and orders for more were placed in the United States during 1916. There the Bethlehem Steel Company had turned out 851 equipments together with limbers and ammunition waggons by the time the United States entered the war in 1917. Thus the unprepared American War economy had an already-equipped artillery production line in being and they converted it to their own use, but as they had already opted for a standard calibre of 75mm they produced their Model 1917 guns in that calibre. By the time the war had ended they had turned out 724 75mm/18pdrs out of a grand total of 2,686 ordered. We shall return to these guns later in the article.
As mentioned above the 18pdr became the workhorse of the British and Allied armies. They formed the major part of the heavy artillery barrages that became the central feature of the Great War campaigns and to them and their ilk must be laid the responsibility for the strange appearance of the Western Front terrain. The field batteries of all the combatant armies were usually allotted the task of barbed wire cutting and destroying the enemy’s front line field fortifications and trenches. During the early months of the war, the 18pdrs were unable to perform this task since virtually all of their ammunition issue was shrapnel. Produced with the man-killing potential of this projectile in mind, shrapnel soon showed itself to be completely unsuited to the conditions of the Western Front. The shrapnel bullets were unable to make any impression on even the most lightly protected fortifications and they could not cut barbed wire either. To add to the Artillery’s troubles, by 1915 the supply of even shrapnel had dwindled to a trickle. The result was the ‘Shell Scandal’ that brought Lloyd George into political power with his Ministry of Munitions, so by 1916 the 18pdrs were firing little else but HE. Even with this projectile the effectiveness of the 18pdrs was often less than satisfactory for they fired in a relatively flat trajectory. When the projectile hit the ground it often had little or no penetrating effect and the resultant detonation often did little more than remove the top soil and leave a small shallow depression. When a shell fell into mud, its effects were often minimal other than removing more soil. The overall result was the strange and eerie ‘desert’ landscapes of 1917 and 1918. After 1918 a team of accountants totted up that well over 100,000,000 rounds were fired by 18pdrs between 1914 and 1918.