Medium Trench Mortar Batteries AIF

About This Unit

This generic listing covers personnel listed in the Emabrkation Roll as having been assigned to Medium Trench Mortar reinforcements.

Each Division had several batteries of Medium and heavy Trench Mortars  - see the respective listing for more information.


The Battle of the Somme ended in November and the British and Empire Armies started rebuilding for the campaigns of 1917. Improved propellants for the 3 and 4-inch Stokes and a new medium mortar were introduced. In the autumn of 1916 a Major Newton developed the use of extra charge rings that slipped over the rear of the bombs that enabled the range of the 3-inch Stokes mortar to be extended to 677 metres. Further improvements in the charge rings saw the range extend to 754 metres and by the beginning of 1918 the 3-inch Stokes to 1,143 metres. This was the maximum range that could be obtained using the cylindrical bomb due to its poor drag coefficient and the mortar barrel having a maximum chamber pressure of two tons per square inch. Major Newton also developed a new medium mortar that used the same firing system as the Stokes mortar. This became the 6-inch Trench Howitzer Mark I, commonly known as the ‘Newton’ or ‘Stokes-Newton’. The design was successful with 1,700 being ordered in late January 1917. Deliveries began in May, and in June the ammunition started arriving in France. In 1917 1,929 Newton mortars were produced with a further 609 in 1918 with ammunition production 239,471 and 1,134,805 rounds respectively. 

The 6-inch mortars replaced the 2-inch medium mortars as soon as they arrived however they had not completely replaced the 2-inch mortars by the beginning of 1918. The mortar weighed 189 kilograms in action in action and fired both 35 kilogram steel and 25 kilogram iron bombs. Both bombs contained 10 kilograms of high explosive. The steel bomb had a minimum range of 460metres and a maximum range of 950 metres and the iron bomb had a minimum range of 90 metres and a maximum range of 1278 metres with a maximum effective range due to dispersion of 1,000 metres.

 We would particularly like to encourage individual historians researchers or members of unit associations to contribute to the development of a more detailed history and photographs pertaining to this unit and its members.

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