The NATO tactical symbol for artillery is a box with a black dot in it: a cannon ball. Yet the first artillery projectile ever recorded, in the de Milemete manuscript of 1327, is not a cannon ball but an arrow or, as we would call it today, an armour-piercing, fin-stabilized projectile. There is no evidence of the discarding ‘sabot’, from the French for ‘boot’, which would enable such a projectile to be fired from a gun with any efficiency. Without a sabot, sufficient pressure from the gun's explosive charge would not be applied to the arrow, suggesting the medieval artist may have heard of guns but not seen one.
The gun itself is not a weapon: it is a delivery system. The projectile or shell is the weapon. Whatever the reason for de Milemete's enigmatic arrow, within a few years, cannon balls were the norm. They were often of stone, which was far cheaper and, from a technical point of view, lighter than metal. Incendiary rounds were also used right from the start. Cannon balls remained the principal form of ammunition for 500 years, their kinetic energy providing the means both for breaching fortifications and for slicing through successive lines of men and horses at great range. In the 16th century, grapeshot—a package of smaller balls which separated after leaving the gun muzzle—and case-shot—still smaller balls—were introduced as efficient close-range killers, making field artillery a practical proposition.
Specialized ammunition was developed for naval warfare, most famously ‘chain shot’—two cannon balls joined by a chain which would orbit murderously and cut through rigging, masts, or people. Exploding shells—initially hollow metal spheres filled with gunpowder—were first introduced in the second half of the 16th century. In 1803 the British Gen Henry Shrapnel devised the shell which still bears his name, containing numerous musket-ball sized projectiles, which were blown from the shell by a ‘burster charge’. Nevertheless, round shot remained the most devastating long-range projectile and at Waterloo Wellington regarded the French shells which landed near him, with their fuses fizzing, with disdain.
In the mid-19th century the cylindro-conical projectile— the familiar bullet or shell-shape—replaced the cannon ball. Ammunition for rifled muzzle-loading guns required ingenious methods to enable it to engage with the rifling, often projections or ‘blisters’ on the projectile, which slotted into the grooves of the rifling. Rifled ordnance and breech-loading, from the 1860s, gave rise to the modern design of artillery shell, with a copper (now often plastic) driving band into which the rifling bites when the shell is rammed into the breech and then fired, imparting the spin to the projectile. The outer diameter of the driving band is greater than the inner diameter of the bore (the top of the ridges of the rifling) by 0.2 to 0.5 mm. As the shell is propelled, spinning, up the barrel, the driving band fills the entire space ensuring obturation—a gas-proof block.
By the start of WW I most armies were equipped with High Explosive (HE) shell—pyroxilin, melinite, and trotyl—and shrapnel, now designed to fire its bullets forward and sideways as it burst before or over the target. The Germans also had HE fragmentation shells, designed for use against troops in the open. Shrapnel, intended for fast-moving battle in the open, was of little use against troops in trenches, however. The British ‘battle bowler’ (steel helmet), also adopted by the USA, was designed to protect against shrapnel bursting directly above.
Artillery's rate of fire, and therefore shell expenditure, increased exponentially. In the 1870-1 Franco-Prussian war an estimated 650, 000 rounds were fired. In the Russo-Japanese war 900, 000 were fired and in 1914-18 about 1 billion. All the combatants in WW I were unprepared for the consumption of artillery shell. By mid-September 1914 all the combatants on the western front were short of ammunition and in 1915 the ‘shell shortage’ became a universal phenomenon. During the war Germany fired 275 million shells; France 200 million; Britain 170 million; Austria-Hungary 70 million; Russia 50 million. On one day—28-9 September 1918—the British army fired nearly a million rounds in its attack on the Hindenburg Line.
Chlorine gas shells were first used by the Germans against the Russians at Bolimov on 31 January 1915. They may have used some at Neuve Chapelle on 10-12 March but the first large scale use of gas was at Langemarck, near Ypres, on 22 April. Much of the poison gas used in the war was released from static cylinders, but this depended on the wind and gas shells, which put the gas exactly where it was wanted, proved far more effective.
An important, related innovation during WW I was the smoke shell. Smoke pots were used to obscure attacking forces on their start lines from 1915, but smoke shell, which could be fired ahead of them, was not available until 1917 and only widely used in 1918. Smoke shell, in combination with high explosive, helped the infantry see where the artillery barrage had got to, and it also hid them from machine guns and rifle fire. A second important innovation was illuminating shell.
In the inter-war period more artillery ammunition was developed including: rockets, notably the Soviet 132 mm M-13 ‘Katyusha’ and M-30 ‘Ivan the Terrible’; concrete-busting rounds for use against fortifications; and even propaganda rounds, containing leaflets. Explosive artillery rounds were big enough to deal with most tanks of the time, but during WW II specialist armour-piercing anti-armour rounds were developed for tank guns and artillery. There are three main types of anti-armour round: a simple high explosive round, in which the explosive is flattened against the outside of the tank and then explodes, blasting fragments off the inside; a shaped charge round, in which the explosive is moulded round the outside of a cone, funnelling the explosive power into a jet of gas which burns a hole through the armour; and solid shot, which mimics the action of the medieval arrow. By applying the great power of an artillery propellent charge to a projectile smaller than the calibre of the gun, a ‘sub-calibre’ device, its effect can be multiplied—like a hammer hitting a nail. In order to transmit the energy from the charge to the sub-calibre projectile a sabot is needed, which acts as a ‘sling’ either to drive an armour-piercing core harder, or to throw a sub-calibre projectile further.
During the 1950s nuclear rounds for artillery were developed, beginning with the giant US 280 mm atomic cannon. Later, they were reduced in size to fit 155 mm NATO and 152 mm Soviet artillery. It is doubtful whether their use would have been a practical proposition (see nuclear weapons).
The artillery shell has been used to carry a wide variety of loads, from smaller projectiles like shrapnel or sub-munitions to chemicals, and even propaganda leaflets. Improvements in ammunition design, exemplified by the extended-range projectiles at the foot of the illustration, have recently enabled artillery to double its range without any major technological innovations
(Click to enlarge)
In the 1980s, there were further developments to conventional ammunition: extended range sub-calibre projectiles (ERSC), using sabots and extended range full-bore (ERFB) projectiles, more streamlined in design than traditional shells, tapered all the way from the driving band. An ERSC round fired from a US 155 mm M-109 howitzer has a range of over 14 miles (22 km) instead of the normal 9 miles (14.6 km). A final new development is ‘base bleed’ technology. This uses a combustible material at the base of the shell which burns, generating gases which fill the vacuum which normally forms behind a shell in flight. It is not a form of rocket assistance, as in a rocket-assisted projectile (RAP), but it does increase the pressure at the base of the shell, largely eliminating base drag, one of three types of drag which act on a shell in flight. Base bleed can increase the range of a round by 13 to 30 per cent. The Austrian GHN-45 155 mm howitzer will fire a non-base bleed ERFB shell to 19 miles (30 km). It will fire a base bleed shell to 24 miles (39 km) and, in the rarefied air in the Middle East, 27 miles (43 km). Comparable artillery systems in use in the 1970s had ranges of 9-11 miles (14-17 km). Thus, in the last twenty years, incremental improvements to artillery ammunition have more than doubled the range of artillery systems without loss of accuracy.
The lethality of ammunition has also increased exponentially, at first due to more efficient fragmentation creating more but smaller fragments. The most unpleasant are flechettes—tiny sharp needles. Flechette rounds enable artillery to fire right onto friendly armoured vehicles, without damaging them, but killing enemy troops all around. Improved Conventional Munitions (ICMs) distribute sub-munitions over a wide area. Finally, there are Fuel Air Explosive (FAE) devices, which spread a cloud of vapour over the target area and then explode it, in just the same way as the fuel-air mixture in a car engine, creating a more even pressure over the target. The USA used these in Vietnam and the Russians in Afghanistan and Chechnya. These can neutralize a vastly greater area than a conventional round, and are also particularly useful for clearing mines.
Bibliography
- Bellamy, Christopher, Red God of War (London, 1986).
- Lee, R. G., Introduction to Battlefield Weapons Systems and Technology (London, 1985)
— Christopher Bellamy
