Dr Richard Fisher
https://doi.org/10.61984/XCWF9375
Abstract
In the 1930s, the Vickers machine gun received a significant upgrade through the introduction of the Mark 8z (1) .303-inch ammunition. Despite only being a relatively minor alteration to the bullet design and the propellant, this extended its effective range from 2,900 yards (2.65 km or 1.65 miles) to 4,500 yards (4.1 km or 2.56 miles) and, as this paper will explain, revolutionised the use of medium machine guns in the British and aligned armies of the Second World War. The implications went beyond the bullet and beyond the machine gun, into the organisation, logistics and even doctrine of the machine gun. This is analysed through the modern British Ministry of Defence capability management framework – the Defence Lines of Development (DLODs) – and this paper explains the intricacies, challenges and ultimate effects of integrating the change into the medium machine gun capability.
Introduction
The Vickers machine gun (MG) was introduced into British Army service in 1912. It was intended as a gradual like-for-like replacement for the Maxim gun that had been in service since 1892. The Vickers was introduced as the ‘Light gun’ as it was 44% lighter than the service pattern Maxim. (2) At the time and into the early years of the First World War, the machine gun – either the Maxim (using both Mark 6 and Mark 7 ammunition) or Vickers (only Mark 7 ammunition) – was not considered suitable for sustained fire and was a ‘weapon of opportunity’. The developments of the First World War resulted in the formation of the Machine Gun Corps (MGC) and the eventual honing of machine gunnery as a distinct capability with its own arm of service.
The drawdown of the British Army in the 1920s saw the MGC disbanded and MGs returned to the establishment of infantry battalions and cavalry regiments. Despite the Vickers MG being used in larger numbers in proportion to the number of infantry divisions, the lack of the imperative of war meant that developments often only drew from the personnel and limited experiences of the parent units which potentially stifled the creativity that had existed in the machine gunners’ own Corps. (3)
Although the doctrine and logistics of MGs in the 1920s were limited by the wider ‘small wars’ concepts that the British Army was facing at the time, technical developments continued. The first trials of a streamlined bullet were conducted in June 1920.(4) The intention was to increase the range of the rifles and machine guns in service at the time and also trials of .5-inch ammunition being proposed for armoured fighting vehicles. After extensive trials and numerous design changes, the streamline .303-inch round would eventually be introduced as the Mark 8z in January 1938.(5) It is the introduction of this round that coincides with several other changes to the British Army with its preparations for the coming Second World War that are explored in this paper.
Method
The literature on small arms development and use is dominated by technical studies and firing data, rather than the wider capability that the equipment delivers.(6) The literature available can be categorised using the defence lines of development (DLODs) in use by the UK Ministry of Defence.(7) This form of historical analysis has been shown to learn lessons for military history and modern defence management from the approach.(8)
This paper examines the implications of the introduction of the Mark 8z ammunition. It does not seek to attribute causality to a particular chain of events but merely identify the interoperability between DLODs that the introduction of the round affected. To determine direct causality, it would require archive material relating to the decision-making for each step of the process and this is outside of the scope of this research. The approach to the research uses ‘consequence’ as a concept where one change has consequential, second and third order, effects in the same or another DLOD.
Research
The introduction of the Mark 8z ammunition for the Vickers MG appears, at first glance, to be a simple enhancement of the equipment aspect of the Medium MG (MMG) capability then in use with the British Army; however, to maximise the efficacy of the capability changes were needed across the DLODs and, subsequently, changes across the DLODs were also possible as a consequence.
Change – Introduction of the Ammunition
Approved in March 1938, the Mark 8z ammunition differed from the in-service Mark 7 ammunition by using a streamlined bullet and a 36.5 grain neonite (nitrocellulose single base) propellant rather than cordite (nitrocellulose and nitroglycerine double base).(9) It was only approved for the use in the Vickers MG and was not to be used in other firearms except in exceptional circumstances.
The direct implication of the new ammunition was an increase in effective range from 2,900 yards for Mark 7 ammunition to 4,500 yards with Mark 8z. The consequences of this were changes across the entire capability, explored below.
As an example of the change in practice, Figure 1 shows the change of effective distance using a Vickers MG fired from Colleville-Montgomery, Normandy. This was previously Colleville-Sur-Orne and the headquarters of 2nd Battalion, The Middlesex Regiment, who were the Divisional (Machine Gun) Battalion of 3rd Division in the British Army during the Second World War.(10) Although they used many positions in this region during their time there between June and July 1944, this shows the extent that their capability changed through the use of Mark 8z ammunition.
Despite its introduction having been the result of many years of research (1920 to 1937) and numerous meetings of the Small Arms Committee, work did not stop and numerous further trials and experiments took place while it was in service and those up to October 1944 were recorded as part of a trial into the barrel life of the Vickers MG when using Mark 8z.(11)
First order effect – Changes to equipment and updated doctrine
Other than the segregation of barrels, it did not require any alterations to the mechanics of the Vickers MG to use and the barrels did not require any special processes in their manufacturing. Furthermore, the case of the .303-inch ammunition was the same for either the Mark 7 or Mark 8z.
Despite there not being any mechanical changes needed to the gun, it was necessary to re-graduate the sight plates and the dial sights (Figure 3) for the new range and trajectory that the Mark 8z gave. These changes in equipment resulted in two versions of each item being required. As an example of the equipment variation, the tangent sight graduated plate was issued as:
• Mark 1 for Mark 7 ammunition, graduated from 100 to 2,900 yards (90 to 2,652 metres);
• Mark 2 for Mark 8z ammunition, graduated from 100 to 3,700 yards (90 to 3,383 metres);(12) and,
• Mark 1* for both Mark 7 and Mark 8z with graduations on each side of the plate so it could be unscrewed and turned over if different ammunition was used.
Other equipment that became available as variants for the Mark 8z ammunition were the slide rules, dial sights and plotters as these were all affected by the different ballistic qualities of the ammunition. Whilst slide rules and plotters were in use with the Mark 7 ammunition, they needed different graduations to reflect the different ranges and ballistic qualities. The dial sights (Figure 3) were not previously an item in machine gun use but were similar to artillery and mortar items. Although indirect fire had been practiced since the First World War, the use of the dial sight consolidated the separate bar foresight and clinometer that had been used to lay the direction and elevation onto the gun. The clinometer then had to be removed from the gun before firing so the fixed attachment of the dial sight meant that the gun could be re-laid more easily during firing.
The introduction of streamline ammunition was not considered a change in doctrine in May 1940 – the extra range merely ‘provided guns greater facilities for flanking and harassing fire and for hitting the enemy at a distance’.(13) Despite this, the increased area of coverage shown in Figure 1 had a consequential effect on doctrine. Table 1 shows the increases in range and area.
The two variants did not wear the barrel in the same manner and the use of the Mark 8z round caused the Mark 7 round to become inaccurate much sooner if used in the same barrel.(14) This created a local logistics issue that could be managed within the gun sections but there were only limited numbers of barrels kept with the gun. Within the gun’s equipment schedule, the number of barrels kept as spares depended on the role of the unit. If a static unit, only one spare barrel was issued, for a unit using Mark 7 ammunition, two were issued and for a unit with Mark 8z ammunition, four were issued.(15) This recognised the greater firepower and likely consumption of ammunition for those units using the Mark 8z. Although not a different item, the increased quantity of barrels begins to exemplify the specificity of the supply chain needed as a result of Mark 8z use.
Second order effects – Training courses, range tables and a specific supply chain
To accommodate the new doctrine (16), that was a consequence of the extended range, revised training courses were developed that ensured the new equipment was included. This new equipment, particularly the dial sight, was not a development of an existing piece of machine gun stores but was potentially familiar to artillery gunners. It replaced the bar foresight and clinometer in the training for each individual machine gunner and the use of the clinometer was limited to fire controllers. (17) It does not appear that additional training time was required and 17 hours were dedicated to instruments and aiming across the four stages of training the machine gunner.(18)
To apply the correct settings to the dial sight, it was necessary to have information on how the ammunition worked in flight. This was included in the range tables for machine gunners. (19)
The specific supply chain for barrels was one example of the subsequent effects on logistics. Others included the equipment identified previously and then the ammunition itself, which also had an impact discussed in the next section.
Third order effects – New training manuals, re-organisation, pre-loaded ammunition belts
To ensure consistent delivery of the required information on training, new copies of training manuals were published. These updated the 1931 editions (20) and were first issued in 1939 (21) with updates and amendments over the course of the Second World War, some of which are reflected in the learning and development applied to the use of the Mark 8z ammunition. (22)
Although not considered a direct consequence of the introduction of the Mark 8z ammunition, at the time of its adoption the British Army was transitioning to a new organisation and separating the machine guns from the infantry battalions in which they had been held in a machine gun company. This was part of the preparation for the apparent forthcoming Second World War. The first Infantry (Machine Gun) Battalion war establishment was provisionally introduced on 18 November 1936 and had 36 Vickers MGs alongside 16 2-pounder anti-tank guns. (23) This reorganisation allowed for Mark 8z ammunition to be sent solely to specific unit types and the infantry battalion, which no longer included Vickers MGs, only required Mark 7 ammunition. Although initially an MG Battalion was a Corps or Army asset, and only attached to divisions as required, from 1941, each Infantry Division had an MG Battalion (and its 36 Vickers MGs) as part of its regular establishment. They were the only element of the Division that required Mark 8z ammunition. The structure and establishment of the MG Battalion changed during the course of the Second World War, changing the anti-tank company to an MG company (bringing the total Vickers MGs to 48 guns) then changing again to a heavy (4.2-inch) mortar company (back to 36 Vickers MGs) and, for a period, becoming a divisional support battalion that also incorporated 20mm light anti-aircraft guns.
By using the specific supply chain mentioned previously, it allowed for Mark 8z ammunition to be segregated at source – the factories that made up the infrastructure – and could be pre-packaged into MG belts, sealed in tin liners for transport and reduce the requirement for belt filling in the gun position, using the belt-filling machines that had formed part of the Vickers MGs equipment up until this point. (24) A sustainability, rather than capability, effect of pre-filling ammunition belts meant that a ‘stripless’ belt could be used. These did not contain the metal strips needed for the belt-filling machine to function and for the ammunition to remain in the correct place in the belts when transported, particularly over rough ground – the pre-filled stripless belts in sealed ammunition liners could use cardboard spacers for the same purpose.
A limited amount of Mark 7 ammunition was still needed in an MG Battalion for the rifles of the personnel and any light machine guns for local defence but it was a small amount by exception whereas the infantry battalion did not need any Mark 8z at all.
Fourth order effects – Mechanisation and fewer men
The use of pre-filled ammunition belts described above reduced not only the equipment required but also the personnel. In the Vickers MG sub-section (one gun) prior to the changes in the 1930s, the No 5 and No 6 of each sub-section was designated as responsible for belt filling or being orderlies. (25) Although this was not their only role, the requirement to fill belts, as well as manage the repair and re-use of the belts themselves, disappeared. The stripless belts in use with Mark 8z ammunition were considered ‘disposable’ to the MG Battalions and returned for salvage and eventual reuse through the ordnance depots in the logistics system.
Another impact on the personnel of the MG Battalion was the mechanisation of the British Army that took place in the 1930s and evidenced through the full mechanisation of the Battalions from 1936 onwards. (26) This process saw the Vickers MG moved by wheeled truck and then eventually tracked vehicle rather than horse-drawn limbered wagon. Therefore, the need for two men of each sub-section to manage the horses and their related equipment also disappeared. The move to wheeled truck for the immediate logistics reduced personnel to just five men per gun, then a further man was removed with the use of the tracked Universal Carrier (Figure 4) as this was able to move ammunition right up to the gun position and even increased the amount of ammunition carried per gun from 3,500 rounds to 4,750 rounds. (27)
Analysis
The relationships between different DLODs in the context of UK MOD capability management is referred to as interoperability and is the overarching theme across a capability. (28) The research above has identified many relationships between actions but it is not possible to identify whether these are causes and effects. There is, however, a direct connection and, in some cases, an effect is not possible, or less likely to be possible, without the preceding action. It is likely that the reduction in the number of men required and the increased mechanisation of MGs would have occurred without the introduction of Mark 8z ammunition. A strong enabler of this was the introduction of pre-loaded ammunition belts and their delivery direct from the ammunition manufacturer. This could have occurred with Mark 7 ammunition and the introduction of stripless belts, which challenged the use of the belt-filling machine in the line with the men. These stripless belts started development in the last years of the First World War with the original intent to reduce metal use. (29) Furthermore, the re-organisation of the British Army’s Vickers MGs and the formation of the Infantry (Machine Gun) Battalions could also have occurred without the introduction of Mark 8z as demonstrated in the First World War with the formation of the Machine Gun Corps and the eventual Machine Gun Battalions in 1918. (30) These elements, with the subsequent specific supply chain, enhanced the MG capability overall but were not dependent upon the introduction of the Mark 8z ammunition.
There were essential changes due to the introduction of the Mark 8z ammunition, such as the new sights, the associated range tables, training manuals and training courses. Any new equipment had the need for this; however, the subsequent effect of the doctrinal changes through the increased range had wider implications as evidenced.
The research also identified, although not as part of the ‘neat’ categories of TEPIDOIL, that some units did not use the Mark 8z ammunition and retained the Mark 7 ammunition for use with their Vickers MGs. In doing so, it limited their capability but it was in limited circumstances where this took place. They include the machine gun platoons established in some infantry battalions in the Middle East and Far East and those machine gun platoons retained in infantry battalions of the Australian military. As described, the majority of equipment remained unchanged from that prior to the introduction of the Mark 8z but there were exceptions where these were secondary units and required amendments to the standard training programmes (31) and information requirements. (32)
Discussion
It may have been that some of the changes described in this research would have been implemented without the introduction of the Mark 8z ammunition; however, these would have resulted in a limited capability change and likely been less impactful.
The tactical effect of the change to the Mark 8z is not fully explored in this paper but the research has shown that the capability was a significant enhancement and the combination of this extended range and the sustained fire capability from the Vickers MG’s water-cooling both likely contributed to its retention in service until 1968, thirty years beyond the introduction of the Mark 8z. In the context of modern defence acquisition, this would likely be considered a very effective Service Life Extension Programme. (33)
With the demise of the Vickers MG, Mark 8z ammunition and Medium Machine Gun capability, (34) the General Purpose Machine Gun used the standard NATO 7.62mm ammunition which limited the range to a mere 2,000 yards (1,800 metres)! (35) Although since extended to 2,500 metres, (36) the familiarity with these relatively short ranges today may well make the casual reader incredulous at the claims of a Vickers firing at up to nearly three miles.
The Editors
This paper has not been double-blind peer reviewed due to the clear attributability to the author. However, it has been subject to direct peer review and delivered as a lecture paper to an academic audience. Amendments and suggestions received from those has been incorporated.
Footnotes
(1) For clarity in this paper, Arabic numerals are used throughout whereas at the date of introduction, the Mark 8z ammunition was officially termed the Mark VIIIz.
(2) J Bostock, The Machine Gunners’ Handbook [3rd Edition] (WH Smith, 1914), 95.
(3) Richard Fisher, ‘The Logistics of Machine Gunnery: Examining the Support Requirements for a Small Element of the Overall Battle’, in Preparing for Battle (Leeds: University of Leeds, 2019).
(4) Small Arms Committee, Streamline Bullets, Minute 279, 25 August 1920.
(5) Small Arms Committee, Ammunition, SA. Streamline Bullet. Report on further trials. Messrs ICI Metals Ltd., Streamline Bullet with Neonite Load approved, Minute 1734, 12 January 1938.
(6) Richard Fisher, British Army Small Arms Studies 1900 to 1970: A Literature Review, in ‘Comparing History: The Development and Effectiveness of Defence Models for Comparative Historical Analysis’, PhD thesis, Cranfield University, Bedfordshire, 2025.
(7) These use the acronym TEPIDOIL for each of the headings: Training, Equipment, Personnel, Information, Doctrine, Organisation, Infrastructure, and Logistics.
(9) The Mark 7 round used cordite and the Mark 7z used nitrocellulose base, however there was not a significant change in the performance of the round as the bullet remained the same in those.
(10) Reginald Fendick, A CANLOAN Officer (Vickers MG Collection & Research Association, 2022).
(11) RJGT Bahin, Vickers Mk I: The assessment of the remaining barrel life when firing Mk 8z ammunition (Military College of Science, Small Arms Branch, October 1944), Appendix A.
(12) Only 3,700 yards was shown on the tangent sight graduated plate as this was considered the maximum range available without the use of the dial sight.
(13) War Office, Army Training Memorandum No 32 (London: His Majesty’s Stationery Office, 1940), 12.
(14) War Office, Army Council Instruction 1464 (November 1940).
(16) War Office, Military Training Pamphlet No. 31 – Medium Machine Guns, their tactics and organisation (His Majesty’s Stationery Office, 1940).
(17) War Office, Small Arms Training, Volume I, Pamphlet No. 7 – .303-inch Machine Gun, Part I – Mechanical Subjects (His Majesty’s Stationery Office, 1939), 52-5.
(18) War Office, Small Arms Training, 1939, 7.
(19) War Office, Range Tables for .303-inch Vickers Machine-Gun (His Majesty’s Stationery Office, 1939).
(20) War Office, Small Arms Training, Volume III – .303-inch Vickers Machine Gun (His Majesty’s Stationery Office, 1931).
(21) War Office, Small Arms Training, 1939.
(22) Bahin.
(23) War Office, An Infantry (Machine Gun) Battalion (fully mechanized), II/1931/12 C/1, 18 November 1936.
(24) Fisher, ‘The Logistics of Machine Gunnery’.
(25) War Office, Machine Gun Training (His Majesty’s Stationery Office, 1925), 31.
(26) War Office, An Infantry (Machine Gun) Battalion (fully mechanized).
(27) Fisher, ‘The Logistics of Machine Gunnery’.
(28) Ministry Of Defence, ‘Defence Lines of Development’, Knowledge in Defence, 2020.
(29) Small Arms Committee, Stripless Machine Gun Belts, Minute 121, 24 July 1918.
(30) Fisher, ‘The Logistics of Machine Gunnery’.
(31) War Office, Small Arms Training, Volume I, Pamphlet No. 7 – .303-inch Machine Gun, Supplement – The Clinometer and Bar Foresight (His Majesty’s Stationery Office, 1940).
(32) Australian Military Forces, Range Table for .303-inch Vickers Machine Gun (Using Mk VII Ammunition) (Australian Military Forces, 1943).
(33) SEBoK contributors, ‘Service Life Extension,’ SEBoK, https://sebokwiki.org/w/index.php?title=Service_Life_Extension&oldid=77384 (accessed January 6, 2026).
(34) Richard Fisher, The CADMID Model for Analysis of Historical Military Capabilities, draft paper.
(36) Ministry of Defence, Close Combat – Lethality: General Purpose Machine Gun 7.62 mm L7A2 (London: Ministry of Defence, 2018), 3-1.
