The transformation of the fighting on the Western Front to trench-warfare in 1914 brought into its own the small, hand held bomb - the hand grenade. A logical development since these weapons had been in use in siege warfare for many centuries: some claim the Chinese first used clay and gunpowder hand bombs in this role in the Second Century AD. It was the round shape of these early siege bombs that gave them their name, i.e. grenade from the French for pomegranate.
The use of hand grenades by the British on the Western Front can be defined into two fairly distinct periods - 1914 to 1915 and 1916 to 1918.
1914 to 1915. When the British entered into the war in 1914, little provision had been made for grenades of any kind, as few senior commanders supposed that there would be a siege warfare element to the war. British generals had plans of dashing cavalry advances to back large scale infantry assaults in a war of movement over open ground. In brief, the Cult of the Offensive.
German generals, to the contrary, had taken aboard the lessons of the Siege of Port Arthur in the Russo-Japanese War (1904-05) and entered the Great War relatively well munitioned with both grenades and trench mortars. They had correctly anticipated the need for these siege weapons for the reduction of the French and Belgian forts. Accordingly, when the unanticipated wide-scale trench-warfare began in late 1914 they, the Germans, were much better equipped than the British. Even in 1914, the famous, and highly effective, German 14in. long potato-masher hand grenade - Steilhandgranate - was in ample supply and, indeed, in various modifications it continued as standard issue until the end of the war and, ultimately, into the Second World War.
The only production model of grenade that the British could muster on the outbreak of hostilities in 1914 was the 1908 Model No. 1 Percussion Grenade, i.e. it exploded on impact when the striker on the grenade head hit an object. It has been described as resembling the medieval mace: a 6in long brass cylindrical shaped head with a 16in. wooden handle (later shortened to 12in.) and weighing nearly 2lbs. This was indeed the classic, 'camel = horse designed by a committee' scenario; and very dangerous too. To list just some of the perverse design features. The detonator was carried separately and had to be installed to activate the grenade. So the bomber had the vicarious choice of either carrying the grenade armed when, any accidental blow to the striker could cause the grenade explode, or, to carry the grenade unarmed, and in an emergency to have to find and install the detonator. Hobson's Choice indeed! The overall length of the grenade - at 22" - virtually ensured that it was so unwieldy that in the confines of the trench or bunker, sooner or later, someone would accidentally knock and activate the percussion head striker with catastrophic consequences. To ensure that the head of the grenade was foremost in flight, a long canvas steamer was attached to the handle of the grenade. When the grenade was thrown, this canvas streamer could easily snag on something close by and the bomber could end up getting blown up by his own grenade.
It had been long realized that the hand grenade could be best delivered by a bowling action, as this gave a much higher trajectory than throwing, with far less risk of a rebound. It was also easier to clear obstacles and to get the grenade to fall into trenches or the entrances to dugouts. For the reasons already stated, the design of the No. 1 Percussion Hand Grenade inherently inhibited its use in a safe and reliable manner. To enhance the safe delivery of the grenade, instructors often suggested that it be reversed and thrown like a dart or a shot-putt. This, of course, completely negated the rationale for providing a throwing handle and made the bowling action impossible. But at least it was safer for the bomber and his colleagues.
It is often suggested that the absence of an adequate supply of hand grenades in 1914-1915 spurred the troops in the trenches into devising their own from empty food tins e.g. for jam, bully beef etc. This is only partially true. It was acknowledged in late 1914 that the British and Empire troops were at a severe tactical disadvantage in the trenches because of a lack of an adequate supply of hand grenades. The then Assistant Director of Fortifications and Works - Col. L. Jackson - was asked to develop a programme for the large scale production of hand grenades. Over the next 12 months he considered 12 design types. None were activated by percussion fuse; all used the former army standard time-fuse duly modified. Two of the more successful types were the self descriptive Jam-Tin (or Double Cylinder) and the Hair Brush (or Racket) Grenades, both of which contained the British high-explosive, ammonal. As the alternative name indicates, the Jam Tin Grenade comprised of an inner and outer tin. The inner tin contained the explosive. The outer tin fully enclosed the inner and the space between the two tins was filled with shrapnel. Two Jam-Tin models were produced, respectively designated No. 8 and 9 Pattern or, Light and Heavy Pattern. This difference in weight being due to the greater weight of H.E. and shrapnel balls in No. 9. The fuses that were developed for the new hand grenade were activated by friction (a special friction creating forearm-band was designed for the bomber units) or a by lighted taper - often substituted for by lighted cigarettes. The Hair Brush grenade - No. 12 Grenade, weighing 3lbs. - was a square steel box, with grooved steel plates located top and bottom, affixed to a wooden paddle to facilitate throwing. Once these two types of hand grenade were proven in service, the Royal Engineers were encouraged to improvise them for the troops at the field level in order to meet the current manufacturing shortfall. And they did so until well into 1915, using such materials as came to hand: scrap metal, barbed wire, broken glass etc. However, the increasing number of accidents arising from the use, or misuse, of these improvised grenades obliged the War Officer to forbid their use on the Western Front in December 1915.
Over-riding all these development difficulties, hung a critical shortage of suitable detonators. Just as the 1915 shell shortage was largely due to a shortage of shell fuses, so the development of new hand grenades was similarly compromised. New contractors had be encouraged, and assisted, to greatly boost production to ensure that a flow of suitable fuses was maintained. This was critical to the war effort on the Western Front.
In May 1915 another of the 12 prototypes hand grenades - No. 5. - was introduced. This hand grenade was based on a completely different concept and was the culmination of an idea proposed by a Belgian engineer, Albert Dewandre, and his associate Captain Leon Roland, and developed by a British engineer, William Mills. When the design was fully refined, it introduced a completely new approach to grenade design. The Mills Bomb, as it became known, was approximately oval-shaped to fit neatly into the clenched fist - it weighed around 1.5lbs. It was time-fused; no more dangerous percussion fuses. The detonator was activated by a spring driven firing pin. The firing pin was restrained by lever that in turn was locked by a safety pin. The body of the grenade was made of cast steel and segmented like a pineapple to facilitate fragmentation. There was prevision for the detonator to be carried separately and added in the field.
In practice the armed grenade was gripped in the bowling hand and the throwing stance taken up. This could be standing, kneeling or even prone. With the other hand the safety pin was withdrawn and the grenade thrown. As the grenade left the hand, the lever restraining the firing pin was released and flew free. The spring loaded firing pin then activated the 5 second time fuse which caused the grenade to explode; hopefully having reached its target in the elapsed 5 seconds. If a shorter time delay was required, the lever could be released in the hand and then, after 2 or 3 seconds, the grenade thrown. This meant over short distances there was little chance for the enemy to throw back the grenade or avoid it. As a tactic, the delay in throwing was deplored by the generals, but frequently employed by the troops.
The Mills Bomb was quickly found to be ideally suited to the British and Empire troops with their background of over-arm bowling in cricket: an average throw length was 20 yards, about the length of a cricket pitch. Although some soldiers claimed, the Mills Bomb was too big - at 3.75in. in length and 2.3in. in diameter - to be grasped comfortably or thrown far enough. The British training manuals of the time stipulated that the trained bomber should be able to drop at least half of his 1.5lb. grenades into 4ft. trench at 30yds.
The Mills Bomb also had the enormous advantage that not only could it be safely transported with the grenade separate from the time fuse, but that once armed by front-line troops it was entirely safe until the safety pin was withdrawn. Even then the grenade was safe until the restraining lever was released. If necessary, when it was decided not to throw the grenade, the safety pin could be replaced (providing the lever had not been released), once more isolating the time fuse.
Unfortunately, manufacturing problems kept the flow of Mills Bombs to the Front at an insufficient level and only 10% of the required production was achieved by September 1915. However, by the end of the year production was up to 40,000 per week. Each Mills Bomb cost around 6 shillings (30p).
Whilst the flow of new designs for hand grenades continued throughout the war, the No.5 grenade, or Mills Bomb, soon became the standard hand grenade of the British and Empire Armies. There were some quite serious initial problems with inefficient, or faulty, restraining levers, strikers and fuses. Accidents rose to one for every 3,000 grenades. But such was the unreliability at the time, of the other manufactured and homemade grenades, this was not considered by the War Office to be that excessive. However, at least some of the Poor Bloody Infantry are known to have thought differently; particularly those who had not been properly trained in its use. Improvements in manufacturing standards were rapidly made, and the worst of these faults largely eliminated. More rigorous training programmes for the troops were instituted and safer techniques for the handling and transportation of grenades were developed.
Although most of the 12 hand grenades mentioned earlier went into limited production, the majority were never adopted on a really large scale. And some were found to be so dangerous in use that they were immediately withdrawn, e.g. the Nos. 13 and 14 Pitcher Grenades. The models, other than the No. 1. Percussion Stick Grenade and the No. 5 Mills Bomb were as follows. The No. 2 the Hale, or Mexican, Stick Grenade. The Nos. 6 and 7 Lemon, Light and Heavy Pattern, Grenades. (The former contained only H.E., whilst the latter also contained steel scrap - both were coke-can in shape). The No. 12, Box Pattern, which was a variation of the Hairbrush Grenade. The Nos. 13 and 14 Pitcher Grenades, mentioned above, that were respectively of light steel and cast iron and contained steel scrap. The No. 18 Percussion Stick-Grenade that was identical to the No.1, except it had a different detonator. The No. 19 Percussion Stick-Grenade Grenade (A redesign of the No. 1 with a cast iron pear shaped body plus a different detonator). The Battye Bomb and the Ball and Oval Bombs.
1916-1918. In 1916, the improved No.23 Mk.II version of the Mills Bomb was introduced. A further redesign was carried out in 1917, which produced the No. 23 Mark III and the No. 36 that was very similar. The Mills Bomb came into its own in the trenches where the labyrinthine nature of the defences made advance without the clearing effect of hand-grenades highly problematic.
In 1917, the light (0.7lb.) No. 34 Egg Grenade was introduced, largely to overcome the complaints about the size and weight of the Mills Bomb. It had a 7 second delay fuse activated by hitting a striker-pin against the heel of the boot. But despite campaigns for the introduction of other grenades - particularly a new percussion grenade - administrative and executive inertia meant nothing ever really challenged the Mills Bomb for the remaining duration of the Great War. And, indeed, long after.
During the Great War, the British and Empire troops were supplied with over 33 million Mills Bombs.
N.B. The author would like to acknowledge the assistance he received from Anthony Saunders' book, Weapons of the Trench War 1914 -1914 (1999), published by Sutton, UK, in the verification of the more arcane technical detail of Great War hand grenades: a most useful reference book.