During the Great War the nature of trench warfare created a proliferation of grenades. Over 50 different types and variations were developed, propelled either by hand or from a rifle. There were explosive grenades, smoke grenades, signals grenades, chemical grenades and even a gas grenade.

In this article and the next r wilr describe a few of the main types which were used by British troops.

Historical Development

The grenade as a weapon of war dates from the 15th century. In its simplest form itconststed of a metal case containing a bursting charge which was exploded by an igniter. The explosion would shatter the case and the resulting fragments caused injury to the enemy. Earliest grenades relied on a fuse being lit by the grenadier before being thrown a practice which could be as hazardous to the thrower as to his opponent!

Large numbers of grenades were used in the Napoleonic Wars and in the Crimea, but their use seems to have dropped away during the latter part of the 19th century. Colonial wars and even the Boer War did not create the conditions needed for grenade warfare. As a result, the Germans were better equipped with grenades at the start of the First World War than the British.


Hand Grenades

Grenades in 1914 were exploded wither by percussion or by igniting a fuse. The former had a spring loaded detonator in the nose which set off the main charge when it struck the ground or some hard object. Fused grenades had various means of being ignited and were generally more reliable than percussion grenades which could fail to go off if they landed in mud.

At the beginning of the war the only British grenade was the Mark 1, adopted in 1900 and shown in Figure 1. This was a percussion grenade with a 5.75" long brass body containing the busting charge. Round the body was a segmented cast iron ring that shattered into fragments when the charge exploded The head of the grenade had a detonator chamber with a striker covered by a brass cap. This cap had to be twisted from safe' to fire' and a safety pin removed to make the grenade live. The body was on a 16" long cane handle which carried a yard of
silk braid, supposedly to aid stability when the missile was thrown. There was a belt hook for carrying.

The disadvantages of trying to hurl such a grenade from a narrow trench are obvious. There were many accidents when the percussion nose inadvertently struck the back wall of the trench. Soemthing more handy was needed.

Various designs were developed, such as the Hair Brush Grenade (below L) and the Jam Tin Grenade (below R). However, the most efficient was the Mills Bomb, developed in 1915 and named after its Scottish inventor, William Mills.



 The Mills Bomb

Born in 1856, Mills was an engineer who was involved in the development of aluminum long before the war. He established the first aluminum foundry in Britain and his work proved invaluable in the wartime demand for this alloy.

He was not concerned with munitions, but in 1914 he met a Belgian engineer who was trying to develop an effective means of igniting grenades. Mills was intrigued and by early 1915 had patented his ideas. The War Office took up the design and the first Mills Bombs were issued to troops by mid-1915. The fact that modern grenades still use the same type of mechanism is a credit to his original invention.

The Mills Bomb (Figure 4) weighed about 1.5 lbs and had a segmented cast iron case. Apart from the busting charge, the case contained a spring operated striker and a fixed detonator. The detonator could be unscrewed, making the grenade safe for transport.

The top of the striker protruded through the casing and was held in place by a lever which lay flat down the outside of the body. This lever was held in place by a retaining pin. When the pin was pulled out (not with the teeth!), the lever would still be kept in place by the thrower's hand. The act of throwing would release the lever and the striker spring would bring down the striker to fire an igniting cap. The flame from the cap lit the fuse, which would burn for 7 seconds before setting off the busting charge. Shorter fuses of 4 second were also used. When the grenade burst, fragments of casing would fly about 20 yards from the center of the explosion. The case was segmented to ensure that it broke into small lethal sections.

A trained man could throw a Mills Bomb about 30 yards and he was expected to drop it into an area of about 10 yards by 4 yards.

The invention of the Mills Bomb made other types of explosive grenades redundant, and production during the war exceeded 50 million.

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