The Mountings, Tripod, Auxiliary, .303 Machine Gun, Mark III” or Sangster mount, attached to the water jacket of the Vickers Mark I water-cooled machine gun.

By Robert G. Segel

One of the rarest and most sought after accessories for the Vickers water-cooled machine gun is the “Mountings, Tripod, Auxiliary, .303 Machine Gun, Marks I, II and III” – otherwise known vernacularly simply as the “Sangster Mount.”

The large 51 pound Mark IV tripod was the standard service mount for the Vickers machine gun and was the appropriate base for controlled aimed fire, either direct or indirect, from an entrenched position. However, by 1915 in World War I, it was recognized, and there emerged a perceived need, for a small auxiliary tripod that could be clamped directly to the water jacket for use in the quick moving forward attack as well as an emergency tripod to be deployed quickly when rapid redeployment from a position was necessitated by incoming enemy fire, to a new position that required the gun to be put into immediate action.

On April 20, 1915, Charles Thomas Brock Sangster, a well-known British engineer and industrialist in the bicycle industry, applied for a patent for just such an auxiliary tripod and a patent was granted on June 8, 1916 (Patent No. 100577).

The use of this auxiliary tripod is stated quite clearly in the British Handbook for the .303-In. Vickers Machine Gun, September 1918: “This auxiliary tripod mounting, which is not intended to replace the Mark IV tripod, is for use as an alternative to it, and will in future be issued on a scale of 1 per machine gun to cavalry and infantry units.”

There were technically three Marks of the mount that ultimately saw service with the differences being slight design changes very early on and two variations of brackets to hold the legs when not in use. . The final, Mark III version with spring leg clamps was officially adopted on October 25, 1917. The Mark designation was not stamped or applied to the units.

The “Sangster” mount actually consisted of two components: the main tripod and clamp assembly and the leg holding clamp bracket. On the Marks I and II, the forward leg holding bracket was essential to hold the legs forward in a horizontal positon. Freeing the legs from the forward holding bracket would allow the legs to drop and be deployed. The Mark III version, the most common used and deployed, used a piston arrangement to hold the legs horizontally thus a simplified forward leg holding bracket was employed. The Mark III was deployed by slightly spreading the three tripod legs, which depressed a piston on the tripod head, allowing the unit to rotate and drop down to a vertical position, which then allowed the legs to be fully splayed. When deployed, the mount allowed a full free 360 degree traverse and a 45 degree elevation.

Again referring to the Handbook for the .303-In. Vickers Machine Gun, September 1918, the mounting consists of the following parts:

1) Three legs, each fitted at one end with a joint for attaching to the crosshead pivot, and at a short distance from the opposite end with a shoe which gives stability to the mounting when firing. The pivot receives the trunnion block to which the saddle of the rear gun band is connected by trunnion screws. The underside of the bracket is so formed that by the action of a spring plunger which passes through the center of the pivot, it admits of the legs being folded down in one direction, but held rigidly in the opposite direction.

A hinged clip – provided with a clamping screw and wing nut – with saddle, complete the rear gun band to which is secured a leather lining for gripping the gun.

2) The front gun band which is of steel (leather lined), is formed with two free ends (leather covered); these ends clip the legs of mounting when folded down. It is provided with a clamping screw and wing nut for securing it to the barrel casing of the gun in such a position that the legs of the mounted, when folded up, shall protrude about 1-inch beyond the spring clip.

3) Two leather straps are provided for transporting the gun with the mounting.

A number of auxiliary tripod front band mountings were issued to the Service that differed from the Number 3 description above and were known as the Mark I. These eliminated the leather straps and merely held the legs in the forward un-deployed position. Interchangeability of the front gun band Mark I among the different rear mounting Marks is not affected.

Warfare methods quickly changed and with the widespread issuance of Lewis guns in 1916, the Lewis was much better suited to be carried forward in infantry assault than the heavy and clumsy water-cooled Vickers. Though issued widely and generally well accepted, particularly in emergency situations, the bane of all foot soldiers is the amount of equipment they must carry and the weight imposed upon them. The 8 pound auxiliary mount was generally discarded to save weight as the need for emergency use was very rare amongst regular infantry. There are very few photographs actually taken in World War I that show the Sangster mount in use among the front line infantry either with the auxiliary mount deployed or just attached to the gun ready for use. However, cavalry units and members of the Motor Machine Gun Corps riding Clyno motorcycles with Mk IV tripods secured to sidecars used the auxiliary mount for rapid dismounting and quickly putting the gun into action. They were officially discontinued for use and declared obsolete in 1921 and scrapped. Few have survived making this a rare and important accessory for a Vickers in a collection.

This article is intended to complement Anthony Williams’ article published in last month’s SAR (Vol. 15, No. 4, January 2012) dedicated to .5-inch Vickers guns and ammunition in order to present some of the feed systems used with those weapons. Both fabric belts and metal disintegrating links are presented for four main types of .5-inch Vickers ammunition, namely the earliest belted .600/.500-inch, the rimless 12.7×81, the semi-rimmed 12.7x81SR and the high velocity semi-rimmed 12.7x120R.

Feeding the Early Vickers in .600/.500-inch

Early .5-inch aircraft Vickers machine guns used the belted .600/.500-inch cartridge. The feeding was achieved by means of a complex and over-engineered disintegrating metallic link using no less than 5 separate rings. The ammunition itself is nowadays an extremely sought after specimen and only available in the world’s most advanced collections. The known surviving links are only a handful nowadays and are probably among the scarcest British disintegrating link for collectors.

Feeding the British Service .5-inch Vickers for the Rimless 12.7×81

The rimless 12.7×81 Vickers ammunition was adopted for British Service in 1924 and is also referred to as the .5”V/580. This ammunition was used in British Service both on Land, Sea and in the Air.

Land Service .5-inch Vickers

On Land, the Mark II, IV and V water-cooled tank guns were fed with a 100-round fabric belt referenced as Mark I. The belt is composed of two strips of cotton fabrics assembled together with riveted brass spacers. Both ends of the belt are fitted with a brass starter tang intended to facilitate the introduction of the belt into the feed block. The starter tangs are marked with the caliber designation, the belt capacity and the manufacturer’s code. One starter tang only also bears inspection markings. The brass spacers are slightly chamfered at the top ends in order to positively seat the shoulder of the cartridge case in the belt. Before World War 2, belts are produced by the company Vickers-Armstrongs Limited and are not dated. During World War 2, belts are produced by the company Thomas French & Sons of Manchester. This company specialized in the production of a very wide range of belts and links in various calibers. These wartime belts by Thomas French are marked with month and date of production.

Naval Service .5-inch Vickers

The water-cooled naval Mark III .5-inch Vickers weapons, most frequently encountered on the quadruple Mark M anti-aircraft mount are fed with a 200-round belt assembled with metallic disintegrating links and wrapped around a spool.

Two types of links were in service. The standard link is of the model Mark II Navy and denoted II N. The link design is a direct scale-up version of the Prideaux links developed by the inventor during WW1 for the .303 Vickers aircraft weapon. The links are marked with the weapon designation .5VMG or .5MG, the model of link II N and the manufacturer’s code. According to the large amount of links used during WW2, at least nine different British manufacturers produced those Mark II N links. For example, the company British Pens Limited of Birmingham (marking BP) produced 14,198,000 Mark II N links during WW2.

With the standard Mark II N links, the connection of belt sections with one another usually requires that a loose cartridge be inserted into the trailing links of each belt. In order to enable the connection of two belt sections together without the need to remove and insert a cartridge, a dedicated connecting link was designed and referenced Connecting Link Mark I Navy and denoted I N. This link is fitted with a half-open central loop which can be directly snapped into the last cartridge of the adjacent belt. This connecting link is marked with the weapon designation .5MG, model of link I N and manufacturer’s code. According to their specific use, these connecting links were produced in a much smaller quantity than the standard Mark II N links. It is suspected that probably only very few manufacturers produced these joining links. So far, the author has only come across Mark I N Connecting Links manufactured by the company British Pens Limited (BP), but there are probably other productions.

Air Service .5-inch Vickers

The .5-inch Vickers was involved in British Air Service with the air-cooled Vickers Class B weapons. Only very few weapons were actually acquired by the British War Office for test purposes. These aircraft weapons were fed with simplified and lightened disintegrating links. These Class B links are nowadays rarely encountered.

Feeding Weapons for the Semi-Rimmed Export 12.7x81SR Vickers Ammunition

According to the British War Office requirements, the Vickers Company was only permitted to export .5-inch weapons using a slightly modified cartridge case to make it semi-rimmed which makes it 12.7x81SR. The Vickers designation of that ammunition was .5”V/565.

Vickers exported a few tens of aircraft weapons chambered for that caliber to Japan and Siam. The disintegrating links used with those exported weapons have not been definitively identified. It is however suspected that the links are the same as those used with the Class B aircraft weapons but this is only speculation pending documented evidence.

Feeding Italian Weapons in 12.7x81SR

Italy adopted the semi-rimmed cartridge 12.7x81SR for their aircraft weapons of domestic design.

The Breda-SAFAT aircraft weapons are fed with disintegrating links of the Prideaux design similar to those used with the British Mark III Naval weapons. Italian made links can be readily identified by the markings exhibiting the Italian manufacturers’ code and the month and year of production. No connecting link was used by Italy. It is not known to the author whether Hungary domestically produced any links to feed their Breda-SAFAT.

The other major Italian aircraft weapons chambered for 12.7x81SR is the Scotti-Isotta Fraschini, which also uses disintegrating links. This weapon uses a feed mechanism where the cartridge is pushed through the links that therefore requires belt links of specific design.

Specimens of Italian push-through links with “hook-and-eye” connection design are known from surviving specimens bearing the markings Mod. 42. It is currently unknown to the author whether these are a late variant of links for the standard Scotti weapons or specific links for another weapon. Any comments by readers would be most appreciated.

Feeding Japanese Weapons in 12.7x81SR

Japan adopted the semi-rimmed 12.7x81SR cartridge to feed the Ho-103 aircraft weapon that was derived from the U.S. .50 cal. Browning. The feeding is achieved with disintegrating links which, unsurprisingly, are derived from the U.S. Browning .50 cal. Links M1. Japanese links are either unmarked or marked with the manufacture’s logo.

Feeding the High Velocity Vickers Class D for Semi-Rimmed 12.7x120R

The water-cooled High Velocity Vickers Class D chambered for 12.7x120SR was fed with disintegrating links. This weapon was never adopted by Britain and only very few specimens were sold to Asian countries. Accordingly surviving specimens of the links are nowadays rarely encountered. Links observed so far are unmarked.