Good evening guys!
The main Italian MG of WWI was an indigenous development, the delayed blowback, water cooled Fiat Revelli Modello 1914.
This MG was selected by reasons of national pride over the Maxim chambered for the then standard italian round in 6.5 x 52 mm. This MG was placed in full production in 1914, and despite being mechanically reliable, its feed system was not the common belt or the less common strip, but a complex and prone to stoppages box ("cage") containing 50 or 100 rounds. It was water cooled, but instead having a Vickers style condensator, it had one with a close circulation by means of a pump. Another detail problem was that the locking knob had a rear movement very close to the hands of the gunner (until it was stopped by a recoil pad, just forward of the trigger mechanism), and this arrangement led to several accidents.
In the interwar years, the italians noticed that the current cartridge was underpowered, so they developed the Breda 8x59 mm, a rebated rim round. While waiting for the introduction of the new Breda M37 MG, the Italian Army also modernized many of the huge stock of Modello 14 MG. The modernization consisted in changing the chamber and barrel for the new 8 mm round, replacing the odd feed mechanism for a typical belt system from the left and an air cooled heavier barrel (briefly and unsuccsessfully, it was attempted an oiling system for lubricating each cartridge, but the oil pump was discarted). Unfortunatelly the problem with the arming knob (which was of cruciform shape) was unsolved. The resulting weapon was the medium MG Fiat Revelli Modello 35, which solved the issues of lack of stopping power and feeding, but with problems of reliability because it suffered from jammings rather often.
Both MG were used by the Italian Army in Abyssinia, the Spanish Civil War and WWII with a rather indifferent record. In the SCW it was used both by the italian troops of CTV (Corpo Truppe Volontarie or Voluntary Troops Corps) , and the francoist army. During the rout of Guadalajara in 1937 (the last attempt to encircle Madrid before shifting the war to the North), the Italians lost to the republicans nearly a hundred of Fiat Revelli 14 and 35. Cheers.