4.2 inch Mk 3 Mortar

4.2 inch Mk 3 Mortar used by the Australian Army during the Second World War until the 1970s is a muzzle loading, smooth bore weapon designed to fire high explosive and chemical projectiles. The mortar consists of a barrel, base plate, bipod mount and two wheeled trailer. The mortar barrel is made from forged steel and has a base plug that fits into a recess on the base plate. The base plate is made from rolled steel and is rectangular in shape. The bipod can be folded out and has provisions for elevation and windage adjustments. The base plate has provisions for towing by the addition of two pneumatic tyres. There is a tow loop attached for vehicle towing.

The 4.2 inch Mk 3 Mortar was introduced into Australian Army service during the Second World War as an infantry support weapon. However, during the 1960s and 1970s the mortar was used to equip light batteries of the Royal Australian Artillery. The mortar was normally towed by a 3/4 ton landrover during its later operational service and was disposed of during the late 1970s.