SOME WW1 BRITISH GRENADES

Version francophone

N°24 Mk I grenade

INTRO : THE WW1 BRITISH GRENADES

HAND GRENADES

N°2 Mk I and Mk II grenade 'Marten Hale'

'Battye' grenade

N°5 Mk I & II, N°23 Mk I, II & III, & N°36 MkI & II 'Mills' grenade

N°34 MkI, MkII, MkIII & MkIV rifle grenade

RIFLE GRENADES

N°20 MkI & MkII rifle grenade

N°24 MkI & Mk II rifle grenade

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British Grenades

One important difference between the British Army and the other ones entering into war in August 1914 was the fact it had recently participated to a conflict during the Boer Wars in South Africa, fighting a non conventional army however equipped with modern weapons. These campaigns learnings had consequences on British artillery evolution, as well as on the introduction of modern grenades, the very first one appearing in 1908. This 'Grenade Nr 1, General Service' equipped the British Expeditionary Corps participating to the fist battles on the continent.

The experience of the early trench fights induced the same need for every country : more grenades, and better ones ! As a consequence, improvised models were produced in parallel to the development of new reglementary ones.

The Mills grenade appearing in 1916 is one of the latter, and will be by far the best hand grenade of the WW1, continuing its international career until the 1970's.

Hand grenades

Percussion grenade MARTEN HALE 'Mexican' *Rifle and hand grenade N°2 MKI and MkII*
		Using the same technological basis than the reglementary percussion hand grenade N°1 MkI, MKII and MkIII General Service made by the Woolwich Royal Laboratory (1908) issued from the Boer war experience, the private company Marten Hale Cotton Powder Ltd manufactured in 1907 a percussion grenade for the Mexican Army. Facing the insufficient production of the model N°1 compared to the British Army needs in 1914, the headquarters adopt this private grenade and name it the Rifle and hand grenade N°2 MKI (the french army will use it as well shortly). The grenade cylindrical brass body was containing the explosive charge. The percussion igniter, working on a pure inertia principle was located inside a central tube, was blocked at rest by a safety pin. A double prefragmentated cast iron belt circled it all. A 40 cm wooden handle with a 90cm ribbon was added for use as a percussion hand grenade having to land vertically on the head in order to explode. A 25 cm long and 7 mm diameter steel rod was replacing the handle for use as a rifle grenade for the British infantry weapons. A 8 mm rod could ne mounted for use with the French Lebels. The hand grenade N°2 MKII only differed by the ribbons length and numbers. This weapon was really insecure, too sensitive once the safety pin was removed. Unknown weight, Tonite explosive
Rifle grenade N°2 Mk I reassembled. Markings : 'THE COTTON POWDER Co Ltd - HALES PATENT LONDON - 8 M/M - B.

Rifle grenade N°2 Mk I. Detail of the body cut in two for trench art making.	Rifle grenade N°2 Mk I. wo of them mounted as a war souvenir trench art item.

Rifle grenade N°2 Mk I - wartime scheme.
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Battye grenade *Major Battye improvised handgrenade*
		Just like most of the fighting nations armies, Great Britain Army had to compensate the lack of reglementary grenades at the beginning of the war by a parallel production of improvised weapons. The Battye grenade was born in 1915 and was an idea of a major named Battye, built on the basis of a simple prefragmented cylinder made in Bethune (France) by thousands. This grenade body was filled with an ammonal explosive load, and closed by a wooden plug. A simple wick or a more complex igniting device (traction or percussion) connected to a 5-seconds delay was introduced through that plug. The use of improvised grenades such as this one was forbidden at the end of 1915 in the British Army, because of too numerous accidents. Total weight 550 g including ammonal explosive load
Battye grenade.	Empty Battye grenade.

Battye grenade - wartime scheme
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Mills rifle and hand grenade *N°5 MkI, II - N°23 MkI, II and III - N° 36 MkI grenade*
		Before the war start, two Belgian citizens - Albert Dewandre (an engineer) and the Captain Léon Roland (from the Compagnie Belge des Munitions Militaires) - designed the principles of this modern grenade : an automatic ignition system fully located inside the grenade body and therefore waterproofed. The start of the great war brutally stopped this invention development (the Captain Roland being capured by the Germans as a prisonner). But a talented English manufacturer, William Mills, who met Dewandre at the end of 1914, made the theoretical concept possible, and introduced a patent as soon as February 1915. The grenade n°5 MkI (Mills patent) finally appeared on the front in May 1915, but its distribution to the fighting units was relatively slow : some British soldiers were not given such weapons before another year. This grenade was made of a outside prefragmented cast iron body, with a lateral filling hole, another hole at its top for plugging the spoon igniting device, and a bigger hole at the bottom for screwing a brass plug giving access to the igniter body. The ignition system was contained into a central tube : a mobile percussion pin compressed with a spring was facing a starter fixed behind the grenade bottom plug. The percussion pin top was attached to an external lever secured by a safety pin. To use the grenade, the soldier had to remove the safety pin and keep the spoon lever pressed with the grenade body inside his palm. When the projectile was launched, the freed spring action moved the lever up, propulsed the percussion pin towards the starter, whose ignition set fire to a delayed wick, finally igniting the detonator after combustion. Safe and waterproof, this grenade has been by far the best handgrenade of WW1, and was even adapted as a rod rifle grenade by the addition of specific devices. The Mills system has been the subject of 3 major evolutions during the war : N°5 MkI and MkII hand grenade : the MkII lever was made more rigid thanks to a bend N°23 MkI, MkII and MkIII hand and rifle grenade : the MkI appeared in 1917 with a narrower base and a base plug drilled with a central threaded hole for the optional screwing of the rod needed to transform the projectile into a rifle grenade. The MkII and MkIII were variants only designed to improve the manufacturing productivity and lower the production costs. N°36 MkI hand grenade : May 1918 evolution, rounder 'belly' for a more stable station in the rifle launching device, and larger safety pin location ears. These differnt version life was so long that this grenade was still in use in WW2, and only removed from the active service in the 70s ! More than 50 millions Mills grenades have been produced during WW1, all variants included, by more than a hundred subcontractors. Its handsome shape, fragmentation properties and internal igniting device both safe and waterproof were the fundamentals of this huge success. Weight 770 g, including the diverse expolosies used (Alumatol + Abelite + Cilferite, or Amatol, or Ammonal + Bellite)
N°5 MkI Mills grenade.	N°5 MkI Mills grenade, front view with the filling hole brass plug.

N°5 MkI Mills grenade. Bottom view, bottom plug removed showing the detonator.	N°5 MkI Mills grenade. Bottom plug detail with manufacturer marks (october 1915 - Calthorpe Motor)

N°5 MkI Mills grenades. The left body has been observed in Flanders Fields, near Hooge.

N°5 MkI Mills grenades. Wartime scheme.
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N°34 hand grenade *Pétard de la IIIe Armée de 12.5cm x 3cm*
		The small and handy German egg grenade ('Eierhandgranate') inspired the British designers who introduced in the end of 1917 a copy made of a cast iron body and a simple percussion igniting plug, with a 5 seconds delay. This new Hand Grenade n°34 is known in 4 successive variants : hand grenade N°34 MkI, ovoidal body shape with a percussion igniter, safety spring and removable safety pin, delay 5 seconds hand grenade N°34 MkII, shape identical to the one of the MkI with a percussion igniting plug, shearable metallic safety wire and safety pin, delay 7 seconds hand grenade N°34 MkIII, elongated ovoidal shape with the MkII percussion pin hand grenade N°34 MkIV, shorten ovoidal shape and prefragmented belt, with the MkII percussion pin All 4 models were equipped with a brass plug closing a lateral filling hole. Unknown weight, alumatol explosive
Handgrenade n°34 Mk III - view showing the charge loading hole plug	Handgrenade n°34 Mk III - igniter threaded hole

Handgrenade n°34 Mk III - dismantled percussion igniter, no detonator
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Rifle grenades

N°20 rifle grenade *N°20 MkI & MkII rifle grenade*
		The new rifle grenade N°3 appears in 1915. This design is inspired from a Marten Hale percussion grenade that solved the safety issues of the N°2 hand and rifle grenade. This improvement was obtained by an ingenious safety system including a impeller whose spin was produced by the wind flow during the early flight trajectory, and was arming the grenade. Unhopefully, this weapon manufacturing was made more complex, hence expensive, because of this system. The N°20 Mk I Rifle Grenade is a simplification of the famous N°3 rifle grenade, dated June 1915 and allowing a cheaper and quicker manufacturing process while keeping identical safety properties. Both the externally prefragmentated body and the internal percussion ingniting system are unchanged, but the arming impeller system is replaced by a simple sliding ring allowed to move backwards on the action of the departure inertia force, and secured at rest by a safety pin. A further simplification of the body manufacturing was almost immediately introduced with the N°20 Mk II rifle grenade : its body external prefragmentation was only made by circular grooves instead of the usual squaring. Like all the other rifle grenades of this kind, these models were used introducing the tail steel rod inside an infantry rifle barrel, and fired using a blank cartridge. This last detail was the major danger of this system, the erroneous use of a conventional ammunition beeing a cause of accidents. Unknown weight, ammonal explosive
N°20 Rifle grenade Mk I with its tail steel rod

N°20 Rifle grenade Mk I, head detail with the detonator-bearer plug dismounted	N°20 Rifle grenade Mk I, top view

N°20 Rifle grenade Mk I - Zoom on the grenade base showing the tail arming system. See the sliding ring retained by a safety pin.	N°20 Rifle grenade Mk I - Wartime scheme
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N°24 rifle grenade *N°24 MkI & Mk II rifle grenade*
		The N°24 Mk I rifle grenade is another simplification of the N°3 to N°20 rifle grenades series, dated June 1917. The modifications only involved some components shapes and dimensions, but the mechanisms and functionning were so identical to the 'parent' models that the use of this new grenade was not requiring any specific instruction. The body prefragmentation scheme was only made of circular grooves. An ultimate simplification was adopted in May 1918 by suppressing all the external prefragmentation grooves of the new N°24 Mk II rifle grenade whose cast iron body was entirely smooth, all other components remaining unchanged. Poids inconnu, ammonal, amatol ou alumatol
N°24 Rifle grenade Mk I. Circular prefragmentation - Picture courtesy Luc Malchair	N°24 Rifle grenade Mk I - Wartime scheme

N°24 Rifle grenade Mk II. Smooth body

N°24 Rifle grenade Mk II. Tail detail with the safety pin	N°24 Rifle grenade Mk II. Head detail with the plug (lost) hole.
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