The Martini-Henry (also known as the Peabody-Martini-Henry) was a breech-loading lever-actuated rifle adopted by the British, combining an action worked on by Friedrich von Martini (based on the Peabody rifle developed by Henry Peabody), with the rifled barrel designed by Scotsman Alexander Henry. It first entered service in 1871 replacing the Snider-Enfield, and variants were used throughout the British Empire for 30 years. It was the first British service rifle that was a true breech-loading rifle using metallic cartridges.
There are four classes of the Martini-Henry rifle: Mark I (released in June 1871), Mark II, Mark III, and Mark IV. There was also an 1877 carbine version with carbine variations that included a Garrison Artillery Carbine, an Artillery Carbine (Mark I, Mark II, and Mark III), and smaller versions designed as training rifles for military cadets. The Mark IV Martini-Henry rifle ended production in the year 1889, but remained in service throughout the British Empire until the end of the First World War.
In their original chambering, the rifles fired a .451-inch (11.455 mm) rimmed cartridge, known today as the .577/450, a bottle-neck design with the same base as the .577 cartridge of the Snider-Enfield and, with 85 grains (5.51 g) of powder, notorious for its heavy recoil. The cartridge case was ejected to the rear when the lever was operated.
The rifle was 49 inches (124.5cm) long, the steel barrel 33.22 inches (84cm). The Henry patent rifling produced a heptagonal barrel with seven grooves with one turn in . The weapon weighed 8 pounds 7 ounces (3.827 kg). A sword bayonet was standard issue for noncommissioned officers; when fitted, the weapon extended to 68 inches (172.7cm) and weight increased to 10 pounds 4 ounces (4.649 kg). The standard bayonet was a socket-type spike, either converted from the older Pattern 1853 (overall length 20.4 inches) or newly produced as the Pattern 1876 (overall length 25 inches). A bayonet designed by Lord Elcho was intended for chopping and other sundry non-combat duties, and featured a double row of teeth so it could be used as a saw; it was not produced in great numbers and was not standard issue.
The rifle was sighted to 1,400 yards (1280m). At 1,200 yards (1110m), 20 shots exhibited a mean deflection from the centre of the group of 27 inches (69.5cm), the highest point on the trajectory was 8 feet (2.44 m) at 500 yards (457.2 m).
A 0.402 calibre model, the Enfield-Martini, incorporating several minor improvements such as a safety catch, was gradually phased in to replace the Martini-Henry from about 1884 onwards. The replacement was gradual so existing stocks of the old ammunition would be used up.
However, before this was complete the decision was made to replace the Martini rifles with the .303 calibre bolt-action magazine Lee-Metford which gave a considerably higher maximum rate of fire. Consequently to avoid having three different rifle calibres in service, the Enfield-Martinis were withdrawn and converted to 0.45 calibre and renamed Martini-Henry "A" and "B" pattern rifles. Some 0.303 calibre blackpowder carbine versions were also produced, known as the Martini-Metford, and even 0.303 calibre cordite carbines, called Martini-Enfields (as opposed to Enfield-Martinis).
During the Martini-Henry period in service, the British army were involved in a large number of colonial wars, most notably the Anglo-Zulu War in 1879. The rifle was used by the company of the 2nd Battalion, 24th Regiment of Foot present at Rorke's Drift. During the battle, approximately 150 British soldiers successfully defended themselves against several thousand Zulus. The weapon was not completely phased out until 1904.
The weapon is partly blamed for the defeat of British troops at Isandlwana prior to Rorke's Drift (in addition to poor tactics and numerical inferiority) - while the Martini-Henry was state of the art, in the African climate the action tended to overheat and foul after heavy use. It would eventually become difficult to move the breech block and reload the rifle. After investigating the matter, the British Army Ordnance Department determined the fragile construction of the rolled brass cartridge and fouling due to the black powder propellant were the main causes of this problem. To correct this, the cartridge was switched from weak rolled brass to stronger drawn brass, and a longer loading lever was incorporated to apply greater torque to operate the mechanism when fouled. These later variants were highly reliable in battle.
A variant known as the Gahendra rifle was produced locally in Nepal. The design was somewhat more advanced than the baseline Martini-Henry, but the rifles were produced by hand, making the quality extremely variable.
The Martini-Henry saw service in WWI in a variety of roles - primarily as a Reserve Arm, but it was also issued (in the early stages of the war) to aircrew for attempting to shoot down observation ballons and other aircraft. Martini-Henrys were also used in the African and Middle Eastern theatres during WWI, in the hands of Native Auxiliary troops.
The lock and breech are held to the stock by a metal bolt (A). The breech is closed by the block (B) which turns on the pin (C) that passes through the rear of the block. The end of the block is rounded to form a knuckle joint with the back of the case (D) which receives the force of the recoil rather than the pin (C).
Below the trigger-guard the lever (E) works a pin (F) which projects the tumbler (G) into the case. The tumbler moves within a notch (H) and acts upon the block, raising it into the firing position or allowing it to fall according to the position of the lever.
The block (B) is hollowed along its upper surface (I) to assist in inserting a cartridge into the firing chamber (J). To explode the cartridge the block is raised to position the firing mechanism (K) against the cartridge. The firing mechanism consists of a helical spring around a pointed metal striker, the tip of which passes through a hole in the face of the block to impact the percussion-cap of the inserted cartridge. As the lever (E) is moved forward the tumbler (G) revolves and one of its arms engages and draws back the spring until the tumbler is firmly locked in the notch (H) and the spring is held by the rest-piece (L) which is pushed into a bend in the lower part of the tumbler.
After firing, the cartridge is partially extracted by the lock. The extractor rotates on a pin (M) and has two vertical arms (N), which are pressed by the rim of the cartridge pushed home into two grooves in the sides of the barrel. A bent arm (O), forming an 80° angle with the extractor arms, is forced down by the dropping block when the lever is pushed forward, so causing the upright arms to extract the cartridge case slightly and allow easier manual full extraction.
As well as British service rifles, the Martini breech action was applied to shotguns by the Greener company of Britain, whose single-shot riot guns were still in service in the 1970s in former British colonies. The Greener 'GP' shotgun, also using the Martini action, was a favourite rough-shooting gun in the mid-20th century.