Good evening, gentlemen.
The french workhorse in the trenches of the Western Front, the well tried, sturdy, reliable Mitrailleuse Hotchkiss Mle. 1914:
Based in the design of an austrian officer, it was the one of the firsts successful gas operated machine guns. In the late XIX century, the patent was bought by Hotchkiss and perfected by an american engineer, L. Benet. It was used by Japan in the russo-japanese war and was there the basis of a series of similar gas operated, strip feed machine guns. The gun was very reliable and robust, but also very (and the american soldiers found that the tripod was too tall). It was chambered in 8 mm Lebel, and also in other calibers, including 7 mm spanish, 7.65 belgian and 30-06.
The Spanish Army first bought the Hotchkiss for the Morocco Wars at the beginning of the past century. In 1914 begun to built at the Oviedo factory with a bronze short butt, and was the main machine gun in both sides at the beginning of the SCW. It was chambered in 7 mm. Later in the war, it was suplemented by french made Mle 1914 at least in the republican side.
Cheers.