Hales rifle grenade

Hales Rifle Grenade (No 3, No 20, No 24, No 35)
Hales rifle grenade, c. 1915
Type	Percussion cap grenade
Place of origin	United Kingdom
Service history
In service	1915-?
Used by	United Kingdom
Wars	World War I
Production history
Designed	1915–1918
Produced	1915-?
Specifications
Weight	1 lb 5 oz (No 3), 1 lb 8 oz (No 20 Mk I)
Filling	Tonite and TNT for the No 3,Ammonal for No 20 and grenades based on it.
Detonation mechanism	Percussion cap fuse

The Hales Rifle Grenade is the name for several rifle grenade used by British forces during World War I. All of these are based on the No 3 design.

To fire the No 3, the user would fit the grenade into the rifle, insert the detonator, lay the rifle on the ground in the correct position, remove the safety pin, pull back the safety pin collar, insert a special blank round into the rifle, then fire.

With variants that lack the vale, the grenade was activated in exactly the same way as the ones that have a vale, but the user did not need to remove the safety pin collar, as it lacks one.

In 1907, Martin Hale developed the rod grenade. "A simple rod was attached to a specialized grenade, inserted into the barrel of a standard service rifle and launched using a blank cartridge." Unfortunately, the British did not immediately adopt the idea and entered World War I without any rifle grenades. However, as soon as the trench warfare started, there was a sudden need for rifle grenades. The British government purchased a rodded variant of the No 2 grenade as a temporary solution.

By 1915, Hales had developed the No 3, which is commonly known as the Hales Rifle Grenade. The Hales grenade was improved throughout World War I to make it more reliable and easier to manufacture. However, production of the grenade was slow. In order to speed rod grenades to the front, the British also made rodded versions of the Mills bomb.

Although a simple approach, launching a rod grenade "...placed an extreme amount of stress on the rifle barrel and the rifle itself, resulting in the need to dedicate specific rifles to the grenade launching role, as they quickly became useless as an accurate firearm. This led to the search for an alternative and resulted in the reappearance of the cup launcher during the latter years of World War I." After World War I, the rod-type rifle grenade was declared obsolete and the remaining Hales were replaced with Mills Bombs shot from a rifle via a cup launcher.

The Hales went through many variations in order to make it more cost effective and effective.

The No 3 started off as the No 3 Mk I. It has an externally segmented body and a wind vane designed to help activate the detonator in mid flight. It uses either Tonite or TNT as its explosive.

The No 3 had several problems; it was difficult to manufacture, as it required precision and was made up of many parts. Another problem occurred with the detonators; like the No 1 Grenade, the No 3 needed a special detonator that was difficult to manufacture. This detonator was also used in the No 2 grenade and was very similar to the one in the No 1 Grenade, which made it harder to mass-produce.