smoke, this had the added advantage of widening the cone of the bullet spread. A star shell with a time fuze (No 25) had been developed and small stocks were held before the war but it was not routine issue. Pre-war experiments with 18-pounder HE shells had been inconclusive in terms of their benefits. However, the first month of the war showed that they were worth having and the first HE rounds arrived in September 1914. This was a different shape to the existing shrapnel shell so a new Mark 2 shrapnel shell was introduced to ensure ballistic compatibility. The original shrapnel shells had a relatively blunt ogive – 1.5 circular radius head (crh), the newer ones were 2 crh. In 1914, the standard HE used by UK artillery was Lyddite, a formulation based on picric acid, this was a powerful explosive but expensive. TNT was introduced, but this too was expensive, particularly in its pure form required for shells so eventually Amatol was adopted. This was a mixture of ammonium nitrate and lower quality TNT, various proportions were used but eventually 80% ammonium nitrate and 20% TNT became standard. The parallel inside walls of the shell made it suitable for filling using pre-formed blocks of explosive as well as pouring. Other types of shell were also introduced, although not as extensively as they were for howitzers and heavier guns. White phosphorus smoke shells became available in small quantities in 1916, and in 1918 chemical and incendiary shells were provided. The latter was a shrapnel type shell using thermite pellets, although a black powder incendiary shell for AA use against Zeppelins was introduced in 1916. Second World War Ammunition After the First World War, the variety of ammunition was reduced, although an armour piercing HE shell was developed. The main change was introduction of a new streamlined HE shell, 4/7.5 crh, giving a significant improvement in range. In the 1930s, the new generation of double base propellant, Cordite W, was also adopted. See also 75 mm Gun M1917 US version 7.7 cm FK 96 n.A. German field gun firing lighter shell 7.7 cm FK 16 German field gun firing lighter shell 76 mm divisional gun M1902 Russian field gun firing lighter shell Canon de 75 modèle 1897 French equivalent but firing a lighter shell Hick, Hargreaves & Co. Ltd. NOF Nottingham List of field guns Surviving examples Royal Artillery Museum,