Ordnance ML 3in (81mm) Mk.II mortar
The origins of the “Ordnance ML 3-in Mk.II mortar” arose from the request of the British Infantry at the end of the WWI to have light artillery batteries for close support. Although the issue was studied, it was finally decided to equip the infantry units with mortars instead of ligth guns due to the enormous consumption of resources and men. The Stokes (Mk.I) mortar type was taken as a basis, but a stronger barrel was installed and the ammunition was improved with the adoption of a more powerful propelling charge to expand its range. It entered service in the early 1930s and remained in service with different improvements until the mid-1960s.
Ordnance ML 3in Mk.II mortar gallery and more info