The Ordnance QF 25-pounder, or more simply 25-pounder or 25-pdr, was the major Australian and British field gun and howitzer during the Second World War, possessing a 3.45-inch (87.6 mm) calibre. It was introduced into service just before the war started, combining high-angle and direct-fire, relatively high rates of fire, and a reasonably lethal shell in a highly mobile piece. Later versions saw the fitting of a muzzle brake to enable higher velocity rounds. Memorials featuring this weapon are sited in many locations around Perth including Kings Park, Nedlands and Guildford. At last count, there were 28 Memorial Guns across Western Australia
The 25-pounder design was the result of studies to replace the 18-pounder field gun and the 4.5-inch howitzer, which had been the main field artillery weapons during the First World War. The idea was to build one equipment with the high velocity of the 18-pounder and the variable propelling charges of the howitzer, firing a shell about halfway between the two in size, around 3.5–4.0 inches (89–102 mm) of about 30 pounds (14 kg). The first Australian unit to be issued with the 25-pounder guns was the 2/3rd Aust Field Regiment who were training in England in 1940. They were equipped with British and Canadian made guns. Production of the 25-pounder guns in Australia did not get underway until the latter stages of 1940 in both government and commercial factories. The first Australian built 25-pounder was completed in May 1941 and the Australian made guns were soon being shipped overseas to Australian regiments on active service. At the end of production in Australia in 1943 over 1500 units had been built.
The 25-pounder remained the standard gun in Australian field artillery regiments until replaced in the early 1960s by the American built M2A2 105mm Howitzer. It did remain in use with Reserve regiments until 1975 when it was finally withdrawn from service.
The 25-pounder Short Mark I, or Baby 25-pr, was the Australian pack gun version of the 25-pounder, first produced in 1943. This was a shortened version of the standard 25-pounder, mounted on the Carriage 25-pr Light, Mark 1. Weighing 1,315 kilograms (2,899 lb), it was around 315 kg (694 lb) lighter than the 25-pounder Mark II. The "Baby" was intended for jungle warfare and was only used in the South West Pacific theatre. The gun could be towed by a jeep or broken down into 13 sections and transported by air.
The Yeramba was an Australian self-propelled howitzer mounting the 25 pounder gun howitzer on an American M3A5 Grant tank hull. They were converted by the Ordnance Factory in Bendigo from 1950 to 1952. The Yeramba was withdrawn from service in 1957 after becoming obsolete and remains the only self-propelled artillery introduced into the Australian Army.
History of the 2/3 Aust Field Regiment
https://vwma.org.au/explore/units/619
https://en.wikipedia.org/wiki/2/3rd_Field_Regiment_(Australia)
Yeramba, the Australian Self Propelled 25 Pounder
https://en.wikipedia.org/wiki/Yeramba