The Revelli Modello 1915, almost universally known as the Villar Perosa (often erroneously hyphenated as Villar-Perosa), is an Italian double barreled pistol-calibre machine gun, often credited as the first submachine gun. It was used during World War I by the Italian Army.
The Villar Perosa was originally patented on the 8th of April 1914 by Bethel Abiel Revelli, an Italian engineer. In 1915, the rights to the patent were bought by Officine di Villar Perosa, from which the weapon gained its name. Production rights were also later given to FIAT.
Revelli had conceived the Villar Perosa as an aircraft observer's gun, but in this role it was ineffective, as it was designed to fire low-powered 9mm Glisenti ammunition which was largely incapable of causing significant damage to enemy aircraft. The low magazine capacity and extremely high fire rate of the weapon also proved inconvenient for the operator, who was likely to spend more time reloading the weapon than firing it.
The Italian Army showed some interest in the weapon and initially fielded it as a portable machine gun for use in the Venetian Alps; the light weight and compact size of the Villar Perosa made it very easy to swiftly transport and set up in rough terrain, where traditional heavier machine guns were not suited. The Villar Perosa was issued to Alpini troops in a small wooden case with a detachable metal shield and bipod.
As the war progressed, the Army began to experiment with the Villar Perosa in a variety of different roles, including as a trench-clearing weapon. It was in this role that the Army decided it was most effective, and early attempts were made to make the weapon suitable for trench combat. These included issuing the Villar Perosa on a wooden tray that the user wore around their chest via a leather strap, and wooden stocked variants that were supposed to make the weapon more ergonomic. In late 1917 the Italian High Command decided to take a different approach and sent a request to Beretta to convert the Villar Perosa into a single-barreled infantry carbine. The result was the Beretta M1918, which was issued to Arditi commandos in 1918.
From 1917 to 1918, the Italian government contracted a Toronto-based electrics company to manufacture Villar Perosa guns with tripod attachments. This version was marketed for export as the Revelli Automatic Machine Gun, but it was not commercially successful. The Austro-Hungarians also developed two copies of the Villar Perosa; one was simply a 9×23mm conversion by Steyr, known as the Sturmpistole M.18, and the other was independently developed by FÉG. Known as the Frommer M.17, it was constructed from two upside-down Frommer Stop machine pistols arranged on a tripod.
After the war ended, the original manufacturer of the weapon, Officine di Villar Perosa, designed a single-barreled version commonly known as the "OVP", which saw use in World War II. The Villar Perosa was retracted from Italian service after the war, and the surplus guns were stripped for their parts by Beretta and Officine di Villar Perosa to produce their single-barreled variants. Consequently, few examples of the Villar Perosa have survived intact and those that do exist are now mostly museum pieces.
The Villar Perosa was a delayed blowback-operated submachine gun consisting of twin receivers joined together side-by-side. Each receiver operated independently and were not mechanically interconnected; they were required to be loaded and cocked separately. The trigger mechanism consisted of a pair of spade grips with button triggers and safety latches. The magazines of the Villar Perosa featured slits in their rears that allowed the user to check how many bullets were left.
The Villar Perosa's bolt rode on a guided lug. Upon firing, the bolt would travel forward with the lug until it reached a curve in the lug's guide, which would cause the bolt to rotate 45°, allowing the striker to move forward and make contact with the primer of the chambered bullet. The bolt would be delayed upon retraction due to the friction it encountered when travelling out of the 45° curve.
A variant of the Villar Perosa was developed specifically for the British Army, which was chambered in the standard British pistol round, .455 Webley. The weapon was taken to Britain by a marketing representative from Officine di Villar Perosa, Mr. D. Bernachi, and demonstrated at Hythe on the 7th of October 1915 and later at RSAF Enfield the same month. The Small Arms Committee filed a report on the weapon to the British Army General Headquarters, who rejected a proposal to purchase a batch of Villar Perosas. Consequently, the demonstration model was the only example in .455 to ever be produced.
An Austro-Hungarian copy of the Villar Perosa was made in 1918, known as the Sturmpistole M.18, made by Steyr. The most notable visual difference is its straight 9×23mm Steyr magazines instead of the curved 9mm Glisenti magazines. It appears to have been issued with the wooden tray arrangement designed for trench combat.