A stalwart of the Italian military inventory became the Beretta Model 1938 series submachine gun which was an interwar form of the World War 1-era Model of 1918. The Model 1938 itself was progressively evolved throughout World War 2 and a final variant was offered as late as 1949 before the Army adopted an all-new, modern submachine gun in the Model 12 during 1959. The type proved a drastic departure from the former design in its use of an all-metal frame with a more advanced overall appearance compared to the rifle-stocked Model 1938 and its offspring.
The new submachine gun was still chambered the 9x19mm Parabellum pistol cartridge and fired from a blowback system of operation. It was well-received by local and foreign forces and went on to see combat service during the Vietnam War (1955-1975), during "The Troubles" concerning Northern Ireland (1968-1998) (by way of Libya), the U.S.-led invasion of Afghanistan (2001-Ongoing), and - more recently - in the 2011 Libyan Civil War. The Model 12 continues in service with the Italians today (2014) and has been purchased by the governments of Bahrain, Brazil (locally-produced by Taurus), Gabon, Guatemala, Guyana, Indonesia (locally-produced by Pindad), Libya, Malta, Nigeria, Saudi Arabia, and Venezuela.
With a new weapons designer (Domenico Salva, having succeeded Tullio Marengoni), Beretta looked to offer a more modern product that could compete with other emerging forms in the lucrative military/police submachine gun market. The result was the compact Model 12 which utilized a short tubular receiver with underslung trigger group, pistol grip, and magazine. The barrel protruded ahead of the frame only slightly and a foregrip was added ahead of the magazine well for a firm two-hand hold. The primary version was a collapsible metal-stocked model which was followed by a (heavier) fixed wooden-stock variant. In either case the barrel measured 7.9 inches long (recessed into the bolt head as a space-saving measure) and the weapon (overall) was just over 7 inches tall - easy to conceal and carry by security forces. Rate-of-fire reached 550 rounds-per-minute with an effective range out to 500 feet. Muzzle velocity was 1,245 feet per second. Sighting was through an iron arrangement that included a two-position rear aperture and a shrouded front post. Construction was of steel stampings and metal pressings with welding where appropriate in an attempt to keep production costs in check.
Chambered for the readily-available 9mm pistol cartridge, the weapon fed from a 20- or 40-round detachable box magazine allowing for some tactical flexibility to be had by the operator. Original versions offered a push-pin-actuated single-shot or burst fire mode.
In 1978, the Model 12S emerged as an improved version that featured an all-new, three-position fire selector switch (safety, single-shot, and burst fire) and manual safety (in addition to the grip safety). The sights were revised and internal workings reinforced. A change to the 9x19mm NATO standard cartridge was also made with a 32-round box magazine introduced. An anti-corrosion finish was applied externally and field-stripping simplified through a tool-less approach. All other functions remained faithful to the original Model 12. The subsequent Model PM12-S2 instituted a third safety feature and has since overtaken the original Model 12 and Model 12S versions.