Britain introduced the Vickers machine gun (the Vickers and Maxim companies had merged). The German version, the Maschinengewehr 08, featured a water-filled cooling sleeve wrapped around the barrel to provide adequate cooling during continuous firing. It could fire up to 2,500 rounds before the barrel needed to be changed or the 4 liters of water contained in the sleeve replaced. The caliber was 7.92 mm and it used 250-round ammunition belts. It was finally phased out only in 1942.
