.303 inch Tracer Mark I to G Mark III
Apart from Ball and Dummy Drill ammunition, tracers were the most numerous of all the special loadings. There were ten marks of tracer approved for service and one of Practice Tracer, the majority of these only being introduced and used during the Second World War.
Prior to 1914 only very limited experimental work had been conducted at Woolwich on tracer bullets, although there was an awareness that machine guns could be carried on aircraft and that a tracer bullet might be required in the future. This work had been carried out by Major Newton but no design had been finalised for production.
When in 1915 air to air combat started, the first tracers utilised were the Buckingham incendiaries which left a smoke trial of burning phosphorus when fired. (See Section 4). There was a demand however for a “flame” tracer that burnt with a bright light and could be easily seen in conditions of low visibility. This led to further work at Woolwich and the testing in France in December 1915 of a new cartridge which was subsequently approved as the “Cartridge S.A. Tracer .303 inch Mark I” but was more commonly simply known as the “RL Tracer”.
Tracer Mark I
"Cartridge S.A. Tracer .303 inch Mark I" was approved in 1914 but was not shown in Lists of Changes.
The case was a normal Berdan primed case. It was originally suggested that the case neck should be blackened as a means of identification but in an attempt at secrecy it was decided that an inverted "VII" should be included in the headstamp. This was sometimes overstamped and some cases were newly made with the inverted headstamp, but the great majority were issued with a normal ball headstamp. The case had no neck crimps to avoid crushing the tracer compound.
The pointed bullet had a cupro-nickel envelope with a lead core in the forward part and about 12 grains of tracer composition pressed into the open base. The tracer burnt with a white light for about 100 yards but was very inaccurate. The bullet weighed 167 grains.
The propellant charge was 32.5 grains of Cordite MDT 5-2 to give a velocity of 2,370 fps.
Left: typical headstamps for the RL Tracer
Right: 1915 Wrapper for the RL Tracer
Tracer Mark VIIT
Although the RL tracer had fulfilled a need, there was soon a demand for a more effective tracer. Aerators, a company best known for their "Sparklet" soda siphons were making 8mm solid bronze bullets for the French and from this developed a .303 inch tracer round which in trials at Hythe traced to 1,000 yards.
"Cartridge S.A.Tracer SPK .303 inch Mark VII.T" was approved on 23rd June 1916 bit was not shown in Lists of Changes. A nitro-cellulose version "Cartridge S.A. Tracer .303 inch SPK (VIIT) NC Mark Iz" was approved in February 1917. The round was generally refered to as the "Sparklet" tracer.
The case was a standard Berdan primed case with the headstamp code "VIIT" or "VIITZ". There was no coloured primer annulus approved. There were no neck crimps.
The bullet was solid bronze bored at the rear to accept about 18 grains of a 17/2 mix of barium peroxide and magnesium. It weighed 167 grains and the exterior was nickel plated, although frequently this has worn off. The trace lasted a minimum of 800 yards.
Initially the propellant charge of the Mark VIIT was 37.5 grains of Cordite MDT 5-2 and the VIITZ 37.5 grains of nitro-cellulose, but later only 41 grains of nitro-cellulose was approved. Muzzle velocity was 2,380 fps at a pressure of between 19.5 and 20.25 tsi.
Letter authorising the nomenclature for the Tracer Mark VIIT and others
Tracer Mark VIIG
The Mark VIIT proved difficult to manufacture, particularly with respect of ensuring the tracer cavity was bored centrally so Royal Laboratory Woolwich developed a new bullet that used the same tracer compound but in a copper canister.
"Cartridge S.A. Tracer SPG .303 inch (VIIG) Mark Iz" was approved on 18th October 1916 but was not shown in Lists of Changes. The title was changed in 1927 to "Cartridge S.A. Tracer .303 inch G Mark I and Iz".
The case was the normal Berdan primed case. The earliest rounds had a ball headstamp for security but normally contained the headstamp code "VIIG". From April 1918 a red primer annulus was approved and from 1928 the headstamp code was "G I". Only in 1927 was an interim code of "VIIGI" used. For the great majority of production the "Z" code for nitro-cellulose was not used.
Canadian produced tracer G Mark I can be identified by a black band around the case above the rim.
The pointed bullet had a cupro-nickel envelope containing a lead core in the front half and a copper canister containing the tracer composition in the rear half. The weight was between 158 and 168 grains and the bullet had no cannelure.
The propellant charge was 41 grains of nitro-cellulose but from 1924 36 grains of Cordite MDT 5-2 was approved. Muzzle velocity was 2,380 fps at a pressure of between 19.5 and 20.25 tsi.
Approval for the nomenclature of the Tracer Mark VIIG
Comparison of Tracer Mark VIIG bullet (left) with Ball Mark VII (right)
Tracer G Mark I
"Cartridge S.A. Tracer .303 inch G Mark I" (and Iz) was simply the retitled Mark VIIG round described above.
It remained in service until 1939 when the Tracer G Mark II became widely issued.
Tracer G Mark II
With a new war approaching and existing stocks of G Mark I failing due to age, a new Kynoch designed flame tracer was introduced. "Cartridge S.A. Tracer .303 inch G Mark II" was approved in July 1937 and shown in Lists of Changes Paragraph B.2624 dated July 1939. "Cartridge S.A. Tracer .303 inch G Mark IIz" was approved at a later date and not shown in Lists of Changes.
The case was a normal Berdan primed service case with a red primer annulus and included the headstamp code "G II" or "G IIZ" ("G 2" or "G 2Z" after 1944). One small lot of GII tracers had the headstamp omitted in error and these were issued in belts for machine gun use.
Some Canadian made cases were Boxer primed and utilised the universal headstamp without the tracer code. These had a red tip for identification.
The bullet had an envelope of CN,CNCS, GM or GMCS with a front core of lead. Behind this was the copper tracer canister containing 10 grains of SR390 tracing composition and 6 grains of SR370 priming composition. The bright flame trace was to 1,000 yards. The bullet was flat based with one cannelure and weighed 154 grains. In some production the tracer canister was closed with a brass washer.
The propellant charge was 35 grains of Cordite MDT 5-2 with one wad or 36 grains of nitro-cellulose to give a velocity ofabout 2,300 fps at a pressure of 19 to 20 tsi.
Tracer G Mark III
In 1939 a new tracer was introduced for the Royal Navy. Although introduced as a brilliant trace that traced from the muzzle, some later production was dark ignition. It may be that the Royal Navy wanted a brighter tracer that was easier to see in conditions of low visibility at sea.
"Cartridge S.A. Tracer .303 inch G Mark III" was approved to design DD/L/9746 in September 1939 for Naval service and shown in Lists of Changes Paragraph B.4043 dated October 1940
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The case was a normal Berdan primed service case with a red primer annulus and included the headstamp code "G III" ("G 3" after 1944).
The bullet had an envelope of Cupro-nickel or gilding metal with a front core of lead/antimony. Behind this was the copper or gilding metal tracer canister containing 10 grains of SR368 tracing composition and 6 grains of SR370 priming composition which was closed by a brass washer. The brilliant flame trace was to 800 yards. The bullet was flat based with one cannelure and weighed 154 grains.
The propellant charge was 35 grains of Cordite MDT 5-2 with one wad to give a velocity ofabout 2,500 fps at a pressure of 19 to 20 tsi.
