Lancaster , read that Wikipedia article , quote:
Second Boer War
The British government initially rejected the gun but other countries bought it, including the South African Republic (Transvaal) government. In the Second Boer War, the British found themselves being fired on by the Boers with their 37 mm Maxim-Nordenfelt versions using ammunition made in Germany. The Boers' Maxim was also a large caliber, belt-fed, water-cooled machine gun that fired explosive rounds (smokeless ammunition) at 450 rounds per minute. Vickers-Maxim shipped either 57 or 50 guns out to the British Army in South Africa, with the first three arriving in time for the Battle of Paardeberg of February 1900. These Mk I versions were mounted on typical field gun type carriages. ( End of quote)
The Maxim Pom-Poms were used by both sides in WW1. In 1915 the German Schutztruppe in South-West Africa dumped at least one such gun into the Otjikoto Lake. I heve seen it years ago in the Tsumeb museum , Namibia. The Germans used DWM made examples as antiaircraft guns and called them Maxim Flak M14.Just at the start of this video https://www.youtube.com/watch?v=EG1DoHPAaRA you can see such an aa gun firing. British used their Mk I or IIs also. There is one in the Imperial War Museum, London, said to have been the first gun to shoot down a Zeppelin over London.
But the Hotchkiss Revolving Cannons, in 37x94R too, also saw some use in WW1. Originally bought by the German and other navies to ward off torpedo boats, they were insufficient and obsolete for this purpose by 1900. So some were relegated to colonial use as they still impressed the natives. German ships and boats on the East African coast and on Lake Tanganjika were armed with these Revolving cannons. Others were tried without success as aa guns, but their firing rate of just 120 rpm maximum (one shot per turn of crank) was far too slow for this purpose. Later, remaining stocks were dismantled. Barrels and ammunition were reused later in WW1 to build light infantry guns like the French Canon d'Infanterie de 37 modèle 1916 TRP or the German 3.7 cm Tankabwehrkanone 1918.