The first Hotchkiss gas operated machine gun was used by several militaries at the beginning of the 20th Century, most notably the Americans, British and the French. The American gun was used to chase Pancho Villa around in 1916-17, and in WW1 for a short time. The British and the French were more attached to the gun and it was used up till the end of WW2.
The Hotchkiss Mk.I, image from Imperial War Museum Collection
The Mk.1 was built in Enfield in .303 caliber. The Americans and the French used their own rifle calibers as well. The gun could be fired from 20 or 30 round strips, or from a belt made of shorter strips if used in vehicles. The odd stock was to accommodate the charging handle, a bit disconcerting due to the fact that when opened it occupies the space your face normally would.
Royal Navy convoy duty 1942
The Brits didn't use these guns with infantry as such, but were used in many other ways. The Royal Navy used them in escort ships, and Q ships (armed trawlers meant to suck U-Boats into a trap) in both World Wars. They were used in early tanks mainly in the Destroyer role, which were meant to smash barbed wire and keep German heads down till the infantry arrived. They were used by the Aussies and the Imperial Camel Corps in the Sinai in 1917 as they were easy to transport by horse, camel back,and early armored cars.
Picture of Royal Navy dual mount, picture by Imperial War Museum
Following video from SitsinShadow's channel