Vickers Heavy Machine Guns

Early Development and WWI Service

By 1917, the Entente allies, facing the massive deployment of German airships, recognized the necessity of increasing the caliber of machine guns used in aviation. The French were the first to attempt to modernize “Vickers” machine guns to their standard 11x59R “Gras” cartridge, enabling the use of tracer, explosive, and incendiary ammunition. Evaluating the effect of heavy machine guns by the allies, Tsarist Russia placed a large order for 11mm Vickers.

It is noteworthy that Russian aviation utilized the large-caliber “Vickers” significantly more extensively compared to other Entente allies. The Russian order for the conversion of several thousand “Vickers” machine guns to 11mm caliber was subcontracted to “Fire Arms Co.” in Hartford, Connecticut, USA. However, initial firing tests revealed that the rifling twist in the barrel was too steep, and the grooves themselves were too deep.

As a result, the depth of the rifling was reduced, and the original twist rate—one turn per 10 inches (254 mm)—was changed to 22 inches (559 mm). This had a positive effect, and a batch of large-caliber Vickers was dispatched to Russia. These heavy machine guns were received with such enthusiasm that an additional order for 1,700 more immediately followed. The weapon’s design, apart from the caliber, was identical to the standard rifle-caliber “Vickers Mk.I” machine gun.

The rate of fire was 600 rounds per minute, with effective incendiary-tracer action at a distance of 1,850 meters. The muzzle velocity of the bullet ranged from 590 to 620 m/s. A large Russian order for French 11x59R cartridges, equipped with incendiary bullets, was also placed in the USA. However, the Russian Revolution left this order unclaimed, with part of it being repurchased by the French and another part remaining in the USA.

The British also showed interest in Allied developments, recognizing that large-caliber machine guns, alongside automatic cannons, could prove useful in future aerial combat. Based on the Franco-American development, the British attempted to adapt the 11mm Vickers as a weapon for observer-gunners. Whether this was an initiative by Vickers engineers or “orders from above” is unknown, but a prototype of such a machine gun appeared in 1918.

Its mechanics did not differ from the base “Vickers Mk.I” model, but for some reason, the belt feed was replaced with a 97-round disc magazine. The disc magazine was operated by the recoil energy of the barrel and was positioned on top of the receiver. Given the increased caliber, the magazine’s design proved to be quite cumbersome, significantly protruding above the already high receiver. This made the machine gun very inconvenient to use in the cramped cockpits of aircraft gunners of that era.

Furthermore, the magazine’s dimensions raised the aiming line unusually high, which did not contribute to firing accuracy. As a result, this machine gun remained a prototype in England. The 11mm Vickers machine gun did not receive a standard model number designation in England; it is most often referred to as the Vickers Model 1918 “Balloon Buster.” Documentation of its use in the concluding battles of World War I is fragmented. It is known, for instance, that Belgian balloon-hunting ace Willy Coppens flew a Hanriot HD.1 fighter armed with an 11mm Vickers.

The .5″ Vickers: Post-War Evolution

In the second half of the 1920s, “Vickers-Armstrong” developed the .5″ Vickers heavy machine gun by simply scaling up the mechanism of the .303″ Vickers Mk I water-cooled machine gun. The new large-caliber “Vickers” was offered in three different versions for the army, air force, and navy. The army version, with water cooling, had a rate of fire of 450 rounds per minute.

The naval variant was externally very similar to the army version, but its rate of fire was increased to 700 rpm by removing a stop that held the toggle while the movable barrel returned to its original position. Additionally, reinforced buffer springs were added to compensate for greater loads. In the aviation version, the design was unified with the naval variant, but the water cooling of the barrel was removed.

The army and naval variants featured a classic ribbed water-cooling jacket of large cross-section, while the aviation variant looked significantly different. Two trapezoidal steel plates were riveted to both sides of the barrel and receiver to compensate for increased loads and to attach to aircraft structural elements. The aviation variant weighed 24 kg, while the naval and army variants weighed 26 kg (excluding cooling water, which added another 4.5 kg).

The barrel had a length of 31 inches (790 mm) or 62 calibers, with an overall length of 47-53 inches (1190-1360 mm). The barrel travel was 1.25 inches (31.75 mm), and the recoil force was 175 kg. The machine guns were equipped with belt feed using disintegrating links for 100 rounds in a standard belt, which weighed 9.7 kg.

In 1927, comparative trials were conducted in Great Britain between the new half-inch Vickers and the latest version of the Browning M1924 machine gun of the same caliber (the well-known M2 machine gun was still undergoing trials in the USA at that time). The Browning was designed around a more powerful cartridge (12.7×99 instead of Vickers’ 12.7×81), whose 46 g bullet left the barrel at a muzzle velocity of 880 m/s. An Admiralty report from 1928 provided the following comparative trial data:

The Vickers machine gun’s rate of fire was adjustable via a knob located outside the receiver, whereas with its American counterpart, the rear plate had to be removed to adjust the buffer force. Overall, in terms of technical characteristics and ease of use, the British machine gun appeared preferable, though due to the smaller volume of water in the cooling radiator, it was more prone to overheating.

Furthermore, it was noted that the Vickers machine gun was less prone to fouling due to the better protection of its moving parts. The Vickers canvas belt was also rated higher. Its links were riveted with metal plates, while the Browning belt was stitched with threads and failed after two or three uses. Metal disintegrating link belts were deemed satisfactory for both machine guns; however, it was noted that the Browning belt links gripped the cartridge more reliably but were also more prone to jamming during sharp bends. Regarding weapon reliability, the Vickers machine gun was found to be less reliable, but this was attributed to one of the first prototypes being used in the trials. The Browning machine gun was more prone to failures at low temperatures, characteristic of aviation versions operating at high altitudes.

In conclusion, it was noted that “the trial results allow us to conclude that the 0.5-inch Vickers has the following advantages: It is lighter and more compact. The method of adjusting the rate of fire is more convenient. It is less prone to fouling due to better protection of internal parts. The design of the canvas belt is more robust.”

RAF representatives also highly praised the heavy Vickers machine gun. However, at the time these machine guns, designated “Vickers Class C,” appeared, RAF leadership concluded that for combating enemy aircraft of the early 1930s, which lacked any serious protection, the rifle-caliber Vickers machine guns were sufficiently effective. They were also faster-firing than the new large-caliber machine guns, which were significantly heavier.

Therefore, the RAF decided against adopting large-caliber machine guns, noting that in the future, if aircraft developed armor, this decision could be reconsidered. By the mid-1930s, when predictions regarding the effectiveness of rifle-caliber machine guns began to materialize, there was no return to the Vickers project; instead, focus immediately shifted to 20mm Hispano cannons.

A small series of “Vickers Class C” aviation machine guns was, however, produced in the early 1930s. The “Vickers” corporation hoped to interest not only the RAF but also potential foreign buyers with its machine gun. 65 “Vickers Class C” machine guns were sold to Japan, 49 to the Kingdom of Siam (now Thailand); however, their subsequent fate remains unknown. During World War II, the “Vickers Class C” machine gun was not in service in either Japan or Siam.

The Army and Navy, however, enthusiastically adopted the new large-caliber machine guns, which were produced in large series during the 1930s and 1940s. For army use as anti-aircraft, tank, and heavy mounted machine guns, versions of the 12.7mm machine guns were produced: “Vickers Mk.I” Model 1932, intended only for portable infantry mounts; Mk.II, launched in parallel with Mk.I, a slightly different variant intended for installation on vehicles and armored vehicles; Mk.IV, an improved infantry mounted machine gun version from 1935; and Mk.V, a universal version for armored vehicles and anti-aircraft mounts, also launched in production in late 1935.

For the Navy, the “Vickers Mk.III” version was produced in quantities of about 12,500 units. In the 1930s, the “Vickers Mk.III,” mounted in quadruple anti-aircraft installations, formed the basis of the close-range air defense for British Navy ships.

Global Adoption and Ammunition Variants

In the late 1920s, assessing the power of American 12.7x99mm ammunition, the “Vickers” company, aiming to compete with Browning’s products in the international market, reasonably assumed that the less powerful domestic 12.7×81 cartridge, all other parameters being equal between English and American machine guns, could be the straw that breaks the camel’s back—that is, become a negative factor tipping the scales towards the competitor.

Because of this, clones of the machine guns described above were developed for the new, more powerful 12.7x120SR cartridge, primarily oriented for export. This included the compact aviation version of the “Vickers Class B” machine gun with a barrel length of 1140 mm and an overall length of 1790 mm, which, however, remained a prototype. And the “Vickers Class D,” with water cooling, sometimes designated as “Vickers HV” (high velocity).

The specifications for the “Vickers Class D” machine gun were as follows: Rate of fire 350 – 450 rounds/min; muzzle velocity of a 45-gram bullet – 927 m/s; effective range 6400 m; altitude reach for the anti-aircraft version – 4750 m. The machine gun’s weight without cooling water was 46 kg, and 55.3 kg with water. A single mount weighed 283 kg, while a twin anti-aircraft mount weighed 1032 kg. The “Vickers Class D” machine gun underwent intensive trials in Great Britain, including attempts to mount it on light tanks, but it was never adopted.

Contrary to popular belief, 12.7x120SR cartridges were not in service in the British Commonwealth. Export sales of the machine gun were also very limited. Siam bought 24 such machine guns, 20 were sold to China, and 48 to Japan. Regarding the “Vickers-B” aviation version, the authoritative English historian of small arms, Anthony Williams, asserts that this machine gun even participated in the aforementioned 1927 competition with Browning. Unfortunately, more detailed information is unavailable.

The origin of the half-inch Vickers cartridge dates back to World War I. Its appearance was predetermined by several reasons. One was the necessity to use bullets large enough to be filled with incendiary and explosive mixtures for combating German airships. The first step in this direction was the use of the French 11x59R “Gras” cartridge, as described above. But even then, it was evident that this cartridge was outdated and did not fully meet the tasks.

The second reason was the need for a heavier bullet to combat armored aircraft that appeared at the end of the war. And finally, the third reason was the emergence of armored vehicles on battlefields, against which conventional rifle bullets proved powerless. While the Germans managed to deploy the specialized 13mm “Mauser” M1918 anti-tank rifle and the large-caliber “TuF” (“Tank und Flieger”) machine gun at the end of the war, the British were somewhat late with developments in this area.

Even after the armistice, the British developed the “Godsal” anti-tank rifle Model 1918, created around .600/.500 inch cartridges, originally intended for elephant hunting. The rifle, however, remained experimental and was forgotten. The cartridge itself underwent various stages of evolution to appear in its final form in 1921 under the designation “Vickers .5V/580” (in this designation – “.5” indicated the caliber in inches, the letter “V” – Vickers, the number 580 – the bullet weight in grains, corresponding to 37.5 grams).

This cartridge was officially adopted by the British Army in 1924 and is known outside the British Empire as 12.7x81mm. The bullet weighed 37.5 grams with an overall cartridge weight of 83 grams. Muzzle velocity was about 750 m/s. Several types of ammunition were developed based on the .5V/580 cartridge: ball, tracer, incendiary, and armor-piercing. Standard ammunition for English machine guns. From top to bottom: 1. .303 British (7.7x56R) – main English cartridge 2. French 11x59R Gras cartridge for WWI large-caliber Vickers machine guns 3. .5V/580 (12.7×81) – standard cartridge for Vickers heavy machine guns 4. .5V/565 (12.7x81SR) – export lightened flanged variant of the cartridge 5. .5V/690 (12.7×120) – enhanced cartridge for Vickers Class B and D machine guns 6. American .5BWG 12.7×99 cartridge.

It appears that the British saw little use in purely armor-piercing cartridges, as their production was stopped in 1935. Their place was taken by semi-armor-piercing rounds, which were widely used in the Navy and Army, as they were significantly cheaper and not greatly different in effectiveness.

Since the British military initially showed little active interest in rearming with Vickers heavy machine guns, the company’s management reasonably began seeking buyers abroad. However, the UK government prohibited the sale of the newest weaponry abroad, even if only partially in service. Vickers management then resorted to a ruse. In early 1923, based on the newly developed “Vickers .5V/580” heavy machine gun cartridge, an export lightened version was developed, designated .5″V/565 or 12.7x81SR.

The cartridge case, as indicated by the designation, underwent changes—a rim appeared, protruding beyond the base diameter of the case. The bullet itself became lighter—36.5 grams with a muzzle velocity of 760 m/s. Mass production of these cartridges was established in variants of standard, armor-piercing, armor-piercing-tracer with “luminous” and “smoky” tracer, and incendiary, structurally equivalent to the “Buckingham” rifle cartridge.

These cartridges were eagerly bought by various countries. In Italy, in particular, licensed production was established. Subsequently, the 12.7x81SR cartridge became the standard Italian large-caliber ammunition in the 1930s and 1940s. Moreover, the Italians significantly expanded the nomenclature of this type of ammunition; in addition to those already mentioned, Italy established production of semi-armor-piercing, armor-piercing-incendiary, incendiary-tracer cartridges, and even explosive ones containing 0.8 g of pentrite.

In the late 1930s, this cartridge migrated to Japan through military cooperation between Axis countries, where its production was also established. In particular, the American Browning AN/M2 aircraft machine gun copied in Japan under the designation Ho-103 used precisely these munitions. Companies “Kynoch” in Birmingham and the state factory “Royal Ordnance Factory” in Aycliffe were engaged in the production of large-caliber cartridges in England.

Model	Caliber (mm)	Action Type	Weight (kg)	Length (mm)	Barrel Length (mm)	Rate of Fire (rpm)	Muzzle Velocity (m/s)	Cartridge Type
Vickers Model 1918	11	Short recoil	12.9	1150	630	600	590-620	11x59R Gras
Vickers Class B	12.7	Short recoil	N/A	1790	1140	600	927	.5V/690 (12.7×120)
Vickers Class C	12.7	Short recoil	24	1220	790	750	880	.5V/580 (12.7×81)