The Beretta M418 is a 6.35 mm (.25 ACP) easily concealed Italian "pocket pistol". The earliest examples were made between 1919 and 1922. There are several versions, including the 1920 (V1 & V2), 1926, 1926 - 31 (V1 & V2), 1934, 318, and 418 models.
Uncertainty surrounds which year Beretta began producing their first .25 calibre pocket pistols. Dates suggested by various sources range between 1919 and 1922. Design work may have started before the First World War, however the company gave precedence to military requirements so work on the compact 6.35 mm only resumed at the end of the conflict. The first version of the gun was very similar to the Model 1922; nearly a scale model in fact, with the single important difference of a spring-loaded firing pin rather than an internal hammer. Mechanically this change was detrimental; it was probably made due to considerations of size. In every other way the two pistols are identical. They share the trigger mechanism fitted with an escaping disconnector, which is typical of all Beretta pistols of that period. A short time afterward a second version (Model 19) appeared, with an automatic grip safety fitted on the frame backstrap. Presumably the safety was added to make up for the reduced level of safety inherent in guns with a striker-type firing pin.
In 1926 a third version (sometimes known as Model 1926) was introduced, in which the firing mechanism was completely redesigned to incorporate a disconnector similar to that used in the Beretta M1923. This simple and economical modification contributed to the fame and commercial success of the 418. It involved a slight change to the left grip, and can easily be seen without dismantling the gun.
Apart from the 1926 alterations, production continued steadily from the beginning of the 1920s until the middle of the 1930s, when Beretta made further changes. Towards 1935 the appearance of the pistol was deemed outdated, and the handgrip was altered to be similar to the Beretta Model 1934. Later, a cocking indicator was also introduced: an extension of the firing pin protruding from the back of the slide. Otherwise, the so-called small Berettas remained more or less unchanged, in that most of the essential parts (barrel, magazine, etc.) were interchangeable. While changes to the gun during this time were minimal, the name was changed often. These various model numbers can be found only in the Beretta catalogues. All guns manufactured up to the mid-1930s are marked simply, IBREV. 1919. Subsequent models until the end of the war are marked Brevettata. They included their date of manufacture in both the Julian Calendar and Fascist-era based Roman numerals. Similar guns produced immediately after the war can be marked Brevettata, but more often as Brevet.