Question: The gun that the BSA Experimental Model 1949 was supposed to replace was used extensively by British and Commonwealth forces throughout what two wars?

Context articles: MCEM 2 submachine gun
BSA Spitfire
Besa machine gun
BL 60-pounder gun
Sten
BSA experimental model 1949
Orița M1941
Type 92 heavy machine gun
Colonial forces of Australia
HMS Magnificent (1766)

MCEM-2 (Machine Carbine Experimental Model 2) submachine gun was produced only in prototype form, but was one of the very first submachine guns to combine wrap-around bolt and magazine in pistol grip, features later copied in the Czechoslovak Sa vz.
 23, Israeli Uzi and a great number of other submachine guns.
 MCEM-2 was the second prototype in a line of experimental submachine guns, designed in Britain in 1944.
 It was envisioned as a possible replacement for the STEN submachine gun then in service.
 The MCEM-2 was developed by Jerzy Podsedkowski, a Polish constructor involved in work on Vis and Mors, who fled from occupied Poland to Britain.
 It is believed that prototypes of MCEM-2 were made before the end of WW2, and its derivatives MCEM-4 and MCEM-6 were tested soon after the war.
 The latter modifications differed mostly in adoption of the rate-reducing mechanism, incorporated into trigger unit; the rate of fire therefore was decreased from 1000 to more realistic 600 rounds per minute.
 Nevertheless, neither prototype was found suitable for adoption, and several years later British army adopted a more conventional submachine gun, the Sterling-Patchett.
The BSA Spitfire was a high-performance BSA motorcycle made from 1966 to 1968 with model designations of MkII, MkIII and MkIV.
 Announced at the Brighton motorcycle show held during September 1965, it was based on the earlier BSA Lightning with a power-upgrade achieved by higher compression-ratio 10.5:1 pistons and two large-bore Amal GP carburetors with velocity stacks it was one of the first BSAs to have 12-volt electrics.
 At introduction in 1966, it was the fastest standard BSA ever produced and the fastest standard motorcycle tested by Motor Cycle with a best run at 123 mph and average of 119.2 mph The Spitfire was used for travelling Marshalls' course duties at the 1967 Isle of Man TT races.
The Besa machine gun was a British version of the Czechoslovak ZB-53 air-cooled, belt-fed machine gun, which in the Czechoslovak army was marked as the TK vz.
 37.
 It was used extensively by the armed forces of United Kingdom during the Second World War, as a mounted machine gun for tanks and other armoured vehicles, to replace the heavier, water-cooled Vickers machine gun.
 Although it required a rather large opening in the tank's armour, it was dependable and reliable.
 The name came from the Birmingham Small Arms Company (BSA), who signed an agreement with "Československá zbrojovka" to manufacture the gun in the UK.
 The War Office ordered the weapon in 1938, and production began in 1939, after modifications.
The Ordnance BL 60-pounder was a British 5 inch (127 mm) heavy field gun designed in 1903–05 to provide a new capability that had been partially met by the interim QF 4.7 inch Gun.
 It was designed for both horse draft and mechanical traction and served throughout the First World War in the main theatres.
 It remained in service with British and Commonwealth forces in the inter-war period and in frontline service with British and South African batteries until 1942 being superseded by the BL 4.5 inch Medium Gun.
The STEN (or Sten gun) was a family of British submachine guns chambered in 9×19mm and used extensively by British and Commonwealth forces throughout World War II and the Korean War.
 They were notable for having a simple design and very low production cost, making them effective insurgency weapons for resistance groups.
The BSA Experimental Model 1949 was a submachine gun of British origin intended to replace the Sten submachine gun.
 The weapon was fed from a 32-round box magazine inserted in the side and had an unusual twist-action bakelite-covered handguard.
The Orița is a 9×19mm Parabellum submachine gun that was manufactured in Romania during World War II and for several years afterwards.
 It was named for Captain Marin Orița (Military Technical Corps, Romanian Army), who is credited in Romania with its design.
 (Other sources describe the Orița as a joint Czech-Romanian project; the Czech Leopold Jašek and the Romanian Nicolae Sterca are also considered to have contributed to its design.)
 The mass production was made by CMC Uzinele Metallurgice Copșa Mică together with Cugir arms factory.
 The first version, Model 1941, entered operational service with the Romanian Army in 1943.
 Two later improved models were the Model 1948, with a fixed wooden stock, and the rare paratrooper Model 1949, with a folding metal stock.
 It remained in service with the Romanian Army until it was replaced in the 1960s by the more powerful Pistol Mitralieră model 1963/1965, a Romanian version of the AK-47 assault rifle.
 The Orița remained in service with the Romanian paramilitaries ("Gărzile Patriotice") until the 1970s.
The Type 92 Heavy Machine Gun (九二式重機関銃 , Kyūni-shiki jū-kikanjū ) entered service in 1932 and was the standard Japanese heavy machine gun used during World War II.
 It was used extensively by the Imperial Japanese Army and Collaborationist Chinese forces.
 Captured weapons were also used extensively by Chinese National Revolutionary Army troops against the Japanese during World War II, and the Korean People's Army against the United Nations forces during the Korean War.
 The Type 92 refers to the Japanese Imperial year 2592 – 1932 in the Gregorian calendar – in which the gun entered service.
 Designed by Kijiro Nambu and built by Hino Motors and Hitachi, total production was about 45,000 guns.
Until Australia(british colony) became a Federation in 1901, each of the six colonial governments was responsible for the defence of their own colony.
 From 1788 until 1870 this was done with British regular forces.
 In all, 24 British infantry regiments served in the Australian colonies.
 Each of the Australian colonies gained responsible government between 1855 and 1890, and while the Colonial Office in London retained control of some affairs, and the colonies were still firmly within the British Empire, the British Governors of the Australian colonies were required to raise their own colonial militia.
 To do this, the colonial Governors had the authority from the British crown to raise military and naval forces.
 Initially these were militias in support of British regulars, but British military support for the colonies ended in 1870, and the colonies assumed their own defence.
 The separate colonies maintained control over their respective militia forces and navies until 1 March 1901, when the colonial forces were all amalgamated into the Commonwealth Forces following the creation of the Commonwealth of Australia.
 Colonial forces, including home raised units, saw action in many of the conflicts of the British Empire during the 19th century.
 Members from British regiments stationed in Australia saw action in India, Afghanistan, the Maori Wars of New Zealand, the Sudan conflict, and the Boer War in South Africa.
HMS "Magnificent" was a 74-gun third-rate ship of the line of the Royal Navy, launched on 20 September 1766 at Deptford Dockyard.
 She was one of the "Ramillies"-class built to update the Navy and replace ships lost following the Seven Years' War.
 She served through two wars before her loss during blockade duty off the French coast.