This may add some more information for you John, I found this write up in my notes and bits (I am sure the author was C W Harding and I typed these notes up from a very poor copy I found somewhere) so I beleive I am correct in crediting them to him. When your memory is getting as bad as mine you need notes :(…
Unfortunately the pictures (sketches) were to far gone to copy so I will try to find out originals to replace them but might not get it completed today.
[i]The name “Rocket” was first used by Eley Brothers of London as a registered trade mark for one of their series of Planet cartridges (See diagram No.4). The name was registered on the 3rd March 1908. These early “Rockets” differed little in composition from any of the other cartridges in the series. In June of 1930, Eley Kynoch were to reuse the name and apply it to a. unique invention.
The idea of tracing the flight of a projectile was not a new invention, since it had first been used in the days of Henry VIII, when cannon balls were used filled with firework mixture. Little advance however was made in tracer or incendiary ammunition until the early 1900’s, but as a result of the Germans using Zeppelins during the 1st World War British Ordinance experts had to find a. way to combat this hazard and their answer lay in the Development of the incendiary bullet. With this advance came the design of the tracer cartridge. The basic principal which military geniuses were attempting to establish was to create a round of ammunition which on firing both the firer and observer could actually trace the path to the target and in doing so the firer could adjust his point of aim without reference to his sights. In order to carry out this function each round of ammunition had obviously to reproduce the characteristics of its ball counterpart or at least as near as human1y possible.
The answer lay in the use of a tracer mix, normally a mixture of magnesium and barium peroxide which was placed in the rear hollowed out section of a service bullet. The bullet was separated from the main powder charge an overshot card. The tracer composition ignited with the flash from the propellant whilst the bullet was still travelling down the barrel and finally burnt out after about 5OO yards.
So much for military ammunition, could such an idea be successfully applied to a shotgun cartridge? Well two such attempts were made and the remainder of this article describes the details of those attempts.
On the 12th February, 1930, Imperial Chemical Industries applied to patent an invention, the design of three men, namely Henry Winder Brownsdon of 43 St. Agnes Road, Moseley, Walter Rule Nimmo of Aparrows Herne Hall, Bushey Heath, Hertfordshire and Lieutenant Colonel George Paton Pollitt of I.C.I. House, Millbank, London.
On the 12th August, 1931 Patent No. 354,718 was finally accepted. The details of this patent are as follows the invention related to an improved method of tracing the flight of shot from a shotgun cartridge. In order to accomplish this a tracer pellet (see-diagram No.1) was inserted in the centre of the base of the shot charge, loosely held in position in the centre of a perforated felt wad, The tracer pellet consisted of a small copper tube filled with mercury fulminate, potassium chlorate and antimony sulphide. One end of the tube was weighted and whilst the other end closest to the powder was covered with a celluloid disc (later replaced with lead paper). Beneath the soft felt wad was a harder felt wad, also perforated in line with the base of the tracer pellet. On firing the flash from the powder melted the seal to the pellet and whilst it was still in motion in the barrel, it ignited.
The first specimens of Rocket Cartridge had an orange paper tube but this was replaced in November 1930 due to identification problems. It was replaced by a blue grey case with dark blue lines and lettering, Every specimen of these cartridges I have encountered have had a milled edge and I believe that this was used so that the sportsman could readily identify them in a cartridge belt by merely running his finger tips over the ends.
When one starts to carefully examine a number of ‘Rocket’ cartridges, so the variations start to appear. With the aid of information from Eley-Kynoch catalogues, specimens from the collections of Chris Goodchild, Eric Wastie and my own collection, I have attempted to draw up a list of those variations.
a. The first Rockets were orange in colour and date between June 1930 and November 1930 (See diagram No.5)
b. Between November 1930 and the 12th August, 1931 the cases were blue/Grey with blue wording including the words "Patent applied for”. See diagram No.7 (Note a1so "the misspelling of the word ‘Shows’.
c. Between August 1931 and the discontinuation of production in 1939 three further specimens are encountered. See diagram No 8. The second of these variations used block capitals for the words Made in Great Britain. The third variation appears in the 1935 catalogue which illustrates the wording as per diagram No.8 but has the words Registered trade mark around the Eley shield.
After August, 1931 a further variation took place in the composition of the tracer pellet. The first specimens up to this date used a copper tracer pellet which had a number of distinct disadvantages which were bourn out by the instructions on the packing cases;
a. The cartridges should not be shot towards dry cover since they had an incendiary effect.
b. Game hit by the pellet should be rejected, this was due to the fact that the pellet was toxic and effected the meat.
By 1932 those two disadvantages had been removed by the introduction of a non toxic disintegrating pellet. The improved Rocket cartridge cannot be identified by case marking from the earlier specimens but packing cases bear the words Eley Improved Rocket cartridge.
During the period of production up to 1939, 'Rockets were produced in 16, 20 and 12 bore and I have encountered specimens in 4, 5, 6, 7 & 8 shot sizes. They were packed in boxes of five (see diagram No.12) and powder loads were either Shultze or Smokeless Diamond.
Rockets produced under licence
In addition to British Rockets at least three other specimens exist of Rockets produced under licence.
a. Australia produced a Rocket with a blue case, no case printing and with a head stamp (a)
b. Fabrique Nationale of Belgium also produced a specimen. This had a blue grey case with dark blue wording. The headstamp is illustrated in diagram No. d and the case is
c. Gyttorp of Sweden also had Rockets produced for thorn at ICI see headstamp No. C. It is interesting to note that these specimens bear a headstamp which differs little from the British counterpart (b) other than in primer size. The case was cream and wording was red. (see diagram no. 10)
During the 1940's Rocket production restarted for the War Office. These were produced in 12 bore only and were cream with red markings bearing a large W.D. broad arrow. See diagram No.9. They came packed in plain cardboard boxes containing 16. The cartridges were ordered for use in 12 bore double barrelled shotguns which had been specially ordered to be manufactured by B.S.A. of Birmingham. As a matter of interest the weapons were sold after the war and can be readily identified by the W.D. broad arrow marking on the actions.
The weapons were issued to R.A.F. for practice by Air gunners, since the flight of a clay pigeon was considered a suitable simulator for enemy aircraft.
Eley Tracer Cartridges
In 1965 Eley Kynoch were to reintroduce this cartridge. It was to be renamed the Tracer cartridge. It differed from the Rocket in that the propellant was a nitro cellulose powder and the tracer pellet was of a more advanced design. It was non-toxic and had a range of some 60 yards to correspond to the range of shot, which differed from its predecessor which carried well past the effective range of the shot. These cartridges were black with wording in silver. They are to be encountered in only 12 bore and were packed in boxes of 10. Today the Tracer has, as I can establish been discontinued with little chance of reintroduction.
Patent No. 3471884
On the l st May, 1936 Marcel Gachassin Lafite of 215 rue Americaine Brussels, Belgium filed a patent application for another form of tracer shot cartridge.
The design was completely different from the ‘Rocket’ and it is interesting to note that the design was filed only weeks after the ICI patent. The design was based on the use of a shot container made of hard rubber (see diagram No.2) one end of which had a circular aperture. At the other end was attached an air brake consisting of fibre and a non flexible pad which prevented the fibre folding up in flight. The fibre brake was dyed with fluorescent paint. The idea of the invention was based on certain proved facts visa;
The tube would reduce friction which was encountered by shot when travelling down the barrel, thereby increasing the effective range.
Shot would not be deformed by contact with the barrel and therefore would present a smooth surface to air resistance again increasing range.
The flight of the shot container would be readily visible to the firer.
As air resistance acted on the brake, the shot would retain its momentum and leave the container through a constriction in the container, acting like a choke therefore tighter shot patterns would be obtained.
I have been unable to establish if this unique design was actually brought into production but the Patent was accepted in May 1931. Since Lafite was a Belgian, one would have expected Fabrique Nationale to produce such a cartridge and yet as previously mentioned F.N. had produced ‘Rockets’ under licence from Eley-Kynoch so it appears that they never adopted the design.[/i]
I will see what I can do to supply the missing pictures.
I can also add a few further remarks to the above; The Eley cartridges were also supplied in boxes of 25 not just the boxes of 5 as mentioned above. Also the misspelling of the word “shows” with the word “shews” actually started on the plain orange case cartridges prior to the milled edge being on the cases.