The submachine gun is an automatic or selective-fire, shoulder-fired weapon chambering pistol-caliber ammunition.
The concept of a submachine gun dates back to World War 1; the trench warfare of that war required effective and compact weapons for short-range fighting in trenches. Additionally, a lightweight and maneuverable fully automatic weapon was desirable to complement light machine guns in both defensive and offensive scenarios. A useful tool to cover the last 200 meters of an assault on enemy positions.
The weapon which can be considered to some extent as the world’s first submachine gun was the Italian Villar-Perosa, which was a twin-barreled automatic weapon that fired 9mm Glisenti pistol ammunition from top-mounted box magazines. It was compact, but its primary tactical role was that of a short-range machine gun. It was therefore usually fired from some sort of mount, and fitted with machine-gun type spade grips instead of the more conventional rifle-type stock usually found on submachine guns.
The first true submachine gun was the Bergmann / Schmeisser MP.18,I, which saw some action during the closing days of the Great War. This was a shoulder-fired weapon, setting the basic pattern for all following weapons of its class.
The inter-war decades produced a significant number of submachine guns, but the tactical niche for these weapons was still unclear to many military experts. It was the Chaco War, the Spanish Civil War and the Russo-Finnish Winter War of 1940 that proved the viability of submachine guns as general-issue weapons for fighting troops.
However, regardless of the large number of available models by the start of World War 2, in most armies, submachine guns were relegated to a secondary role. For example, the very technically advanced Heer (Hitler’s Army) issued MP-38 and MP-40 submachine guns to infantry troops in proportions of about one SMG per ten bolt action rifles.
It was the Red (Soviet) Army which issued PPSh-41 submachine guns as primary infantry weapons to entire companies and battalions. Despite the success of several of the new submachine guns developed during WW2, this also marked the start of the decline of submachine guns as primary infantry weapons.
The appearance of the assault rifle, which while only slightly heavier than most submachine gun’s, had a much longer effective range – put an abrupt end to their use by the infantry in the Soviet army.
On the other hand, the NATO countries still issue 9mm submachine guns to many non-infantry units and certain soldiers in the infantry and special forces for specified purposes. For instance they are useful as Personal Defense Weapons for vehicle crew and as close quarter combat weapons for special forces. They fill some kind of “middle ground” to complement relatively large and heavy semi-automatic or fully-automatic rifles firing powerful 7,62×51 NATO ammunition.
The appearance (and proliferation) of light-caliber assault rifles in the 1960’s, marked the final phase in the history of submachine guns as a general-issue infantry weapon.
Despite what has been noted above, it must be said that submachine guns still possess several qualities that are very useful in certain military scenarios. For example, submachine guns can be easily silenced, making them very useful for various special operations forces.
Police and security use of submachine guns, on the other hand, has greatly increased over the last 30 or 40 years. The proliferation of international terrorism, drugs trafficking, criminal gangs and other violent criminals forced many police forces to adopt a variety of submachine guns for special police teams.
Compact submachine guns, which appeared during the 1960’s and 1970’s, such as the Micro-Uzi or HK MP5k, were quickly adopted by various VIP protection teams that favored compact size combined with the massive short-range firepower of such guns. Of course, folks on the wrong side of the law also saw the benefits of submachine guns. More than a few gangsters, outlaws and various terrorists used submachine guns, starting with the iconic “Chicago typewriter” (Thompson submachine gun Model 1921) and up to the Czechoslovak Scorpion or Croatian Agram 2000.