The Revelli Mod.15 - commonly known as the "Villar Perosa" - is sometimes considered to be the first submachine gun. Whether it qualifies as a "true" SMG is up for debate, but there is no doubt that this gun is certainly the predecessor to the modern submachine gun. It was first patented in April 1914 by Col. Abiel Bethel Revelli, the prolific Italian arms engineer, and was initially produced at Officine di Villar Perosa, a small plant on the outskirts of Turin. The Villar Perosa consisted of two automatic blowback guns fixed side-by-side, with spade grips and top-loading magazines. The chambering was for a pistol cartridge, 9mm Glistenti - the basis for its consideration as an early SMG.
It is often claimed that this gun was originally designed for aircraft. In fact, this is not true. The original intent was to provide a lightweight, sub-compact machine gun for the , Italy's mobile infantry. Early photographs even show the Villar Perosa mounted to the handles of a bicycle, which would seem bizarre at face value, but there is a degree of rationale behind it. The small frame of a bicycle could certainly not support the weight or recoil of a full-caliber machine gun, therefore it must have occurred to Col. Revelli that a 9mm gun would be more practical. The twin barrels would seem to be an attempt to make up for the lack of individual firepower that the pistol caliber would provide.
The end result is a weapon that was, in theory, well-suited to the ___'s requirements - an automatic machine gun that could be carried by a single infantryman, on foot or on bike, with relative ease.
The Villar Perosa on an anti-aircraft mount and fixed to a bicycle
The decision to mount these guns on aircraft came later, when Italy entered into World War I on the side of the Allies. In 1915 the Italian Army was under-prepared and had very few machine guns at its disposal; the Perino was too expensive and was cancelled after only 100 units, and production of the Fiat-Revelli - which had only been adopted the previous year - was coming along at an unsatisfactory rate. It was therefore decided to press the Villar Perosa into general service, for practically every role it could fill. Production was handed over to the Fiat factory in Turin and the gun was officially adopted as the Fiat Mod.15. The first hundred-or-so units were reserved for the air force, and special mounts were developed to fit them to the observer seats of biplanes. The gun was completely impractical for this role, as the 9mm Glisenti cartridge was short-ranged and far too underpowered to do any appreciable damage to a well-built aircraft. It was replaced as soon as full-caliber aircraft machine guns became available to the Italians, mostly Lewis guns donated from Britain.
Other roles that the Villar Perosa was fielded in were that of an anti-aircraft gun and a vehicle-mounted machine gun, and it was probably ineffective at both. Where it performed best was as an infantry weapon, as it was intended. While at an obvious firepower disadvantage to a full-caliber MG, the small, lightweight build of the Villar Perosa lent itself well to the harsh mountainous terrain that characterized the Austro-Italian Front. For infantry, the Villar Perosa was issued in a small wooden box, with a detachable bipod and gunner's shield. It was operated by a team of two, a gunner and a loader. While the gun could technically be operated by a single man without much trouble, both magazines would have been depleted very quickly, as the fire rate was over 1,200 rounds per minute! Thus, it was helpful to have another man load the gun, as reloading would have been frequent.
The Villar Perosa in an infantry role during World War I
The Villar Perosa's potential as a trench-clearing weapon was noticed very quickly and by 1916, Col. Revelli had already developed a single-barreled version with a rifle stock, made at Fiat. After observing this prototype demonstrated, Italian Test Commission approached two other firms, Ansaldo and Beretta, to adapt the Villar Perosa in a similar fashion and in 1917 the three designs were tested against each other. The Beretta gun came out the best and was adopted in early 1918 as the Moschetto Automatico Revelli-Beretta. It was issued in limited numbers to Arditi commandos in the closing stages of the war. The majority of existing Villar Perosa guns were taken apart to be converted into Beretta submachine guns after World War I.
British version
In 1915 the Revelli was demonstrated before the Small Arms Committee in Britain by Dr. Bernachi, an Italian representative from Officine di Villar Perosa. Tests were conducted at Hythe and Enfield in October and the SAC filed a report on the gun that referred to it as the "Villar Perosa machine gun", coining the now-ubiquitous name. The report described the gun as "two long-barreled machine gun pistols connected together" and concluded that it was "very suitable for trench work". Subsequently, Officine di Villar Perosa produced a trials model in .455 Webley Automatic and sent it to the SAC, but by January 1916 the Army General Staff had decided that it was not interested in the gun and there was no chance of adoption in the UK.
The .455 Villar Perosa, of which only one was ever produced
Austro-Hungarian copies
Both the Austrians and the Hungarians made attempts to copy the Villar Perosa. The Hungarian version came in 1917 and was designed by Rudolf Frommer. It consisted of a tripod frame that mounted two upside-down Frommer Stop handguns converted into machine pistols with extended magazines. A pair of spade grips operated the triggers. The Austrian effort was known as the Sturmpistole and was produced in 1918 at Steyr. It was an almost exact clone of the original Italian model, with the only real difference being that it was chambered in the Austrian 9x23mm cartridge. It was issued to Austrian stormtroopers on a wooden tray, designed to strap around their chests. This was an attempt to make it a "walking fire" weapon that could be operated by a single man in an assault role.
The Hungarian copy of the Villar Perosa, using the Frommer action