MP5]] submachine gun is widely used by law enforcement tactical teams and military forces.
A submachine gun (SMG) is an automatic carbine, designed to fire pistol cartridges. It combines the automatic fire of a machine gun with the cartridge of a pistol. The submachine gun was invented during World War I (1914 1918), but the zenith of its use was World War II (1939 1945) when millions of weapons of this type were manufactured. Today the submachine gun has mostly been replaced by the assault rifle for military use. (The assault rifle uses an intermediate-power cartridge with more power than a pistol but less than a standard rifle or battle rifle.)  Even in roles where it has been most used such as vehicle crews and personal defence (PDW), the SMG has been made redundant by weapons like the Colt M4. A major factor is the common use of body armour, where pistol calibers are insufficient for penetration - therefore the SMG is predominant in the civil security sector and is becoming obsolete in military use.
In the early 20th century, experiments were made by converting stocked pistols from semi to fully automatic. Stocked automatic weapons firing pistol rounds were developed around the same time during World War I, by Italy, Germany, and the United States. The first dedicated designs were developed in the latter stages of World War I both as improvements on earlier stocked pistols, and to offer an advantage in trench warfare. They were popularized in the 1920s and 1930s as weapon of choice of American gangsters and police, in the form of the Thompson submachine gun, commonly referred to as the "Tommy Gun". Submachine guns rose to prominence as a front line close-quarters combat weapon and commando firearm during World War II. They are now widely used by police SWAT, military commando, paramilitary, and counter-terrorism team members for a variety of situations. Submachine guns are highly effective in close quarters; their lower-powered pistol cartridges make them generally more controllable in fully automatic fire compared to assault rifles, while their small size and light weight grant maneuverability. Pistol cartridges generally have low effectiveness against targets protected by body armor or cover, and are short-ranged compared to intermediate and rifle cartridges.
19th century to 1920
Thompson]] 1928A1 with box-type magazine. The first automatic weapon to fire a pistol round was a scaled-down version of the Maxim machine gun, used for demonstrations in marketing the Maxim in the late 19th century, especially when a full-sized firing range was not available. First-generation submachine guns were characterized by machined metal parts and blowback designs with the bolt directly behind the barrel. The submachine gun appeared during the later stages of World War I. It first saw action in trench warfare where grenades, pistols, sharpened entrenching tools, improvised clubs, and bayonets were commonly employed.
Luger]]' Lange Pistole 08 with 32 round Trommel-Magazin 08 and removable stock. The Italians developed the Villar Perosa, introducing it in 1915. It fired pistol caliber 9 mm Glisenti ammunition, but was not a submachine gun in the sense that the weapon type would later be defined, as it could not be fired from the shoulder and without support. Originally developed as an aircraft weapon, it also saw some use by infantry as a light machine gun. This odd design was eventually modified to become a traditional submachine gun, the OVP 1918 that evolved into the Beretta 1918 after the end of World War I.
The Bergmann MP18 is the first true submachine gun and had been used intensively starting with Operation Michael in March 1918.
The Thompson submachine gun program began in roughly the same period. The only pictures of SMGs used in combat and reports of captured SMGs refer to MP18 captured in France after the German Spring Offensive.
The Beretta 1918 had a traditional wooden stock, a 25-round box magazine, and had a cyclic rate of fire of 900 rounds per minute. The Germans had been using heavier versions of P08 pistols, equipped with larger capacity "snail" drum magazine, and longer barrel; these were semi-automatic. Bergmann, by 1918 had developed the MP18. The MP18 used 9x19mm Parabellum round in a snail-drum magazine. The MP18 was used in significant numbers by the German stormtroopers who, in conjunction with infiltration tactics, achieved some notable successes in the final year of the war. They were not enough to prevent Germany's collapse in November 1918.
The Thompson submachine guns had been in development at approximately the same time as the Bergman and Beretta, but development was put on hold in 1917, when the US and the weapon's designer (Thompson) entered the war. The design was completed afterwards and used a different internal system from the MP18 or Beretta, but it had missed its chance to be the first purpose-designed submachine gun to enter service. It went on to serve as the basis for later weapons and have the longest active service life of the three.
1920 to 1950
In the interwar period the submachine gun became notorious in the US as a gangster weapon; the image of pinstripe-suited James Cagney types wielding drum-magazine Thompsons caused some military planners to shun the weapon. It was also used by the police, but many criminals favored the M1918 Browning Automatic Rifle. The submachine gun was gradually accepted by many militaries, with many countries developing their own designs over the period, especially in the 1930s.
Argentina manufactured a wide range of high quality submachine guns during the interwar years, most notably the Hafdasa C-4 and Halcon M-1943 which were chambered in 9x19mm Parabellum and .45 ACP calibres depending on service. A weapon ahead of its time was the Hafdasa C-2 machine pistol issued to armoured vehicle personnel which would be today classed as a Personal Defense Weapon.
In the Soviet Union, the PPD34 and PPD34/38 were developed. In France the STA 1922 was adopted as MAS 1924 and evolved into MAS-35 later adopted as MAS-38 using the 7.65mm Long round of the Pistol PA 35, a cartridge derived from the .30 Pedersen. In Germany some improvements on the MP18 were employed, namely the MP28/II and the MP34. Also, Nazi Germany adopted the MP38, unique in that it used no wood and a folding metal stock, though it used a similar number of stampings as the MAS. Italy further developed a number of its own designs (see list of Italian submachine guns), with similar attempts at improvements in lower production cost, quality, or weight.
During the invasion of Poland by Nazi Germany in 1939, the MP38 production was still just starting and only a few thousand were in service, but it proved very effective especially in close quarters urban combat. It was far more practical and effective in those environments than the standard-issue German rifle, the Kar 98K. From it, the nearly identical, but safer and cheaper to make, MP40 was developed; about a million MP40s were made in World War II. The MP40's design used even more stampings, and less strategically important metals such as aluminum, but still managed to be lighter because it avoided some of the heavier machined parts of the MP38.
Britain adopted the Lanchester submachine gun, based on the MP28/II. Britain was also interested in acquiring M/31 Suomis but this project was canceled in 1939 when Finland needed every one for her own defense. However the high cost of manufacture and low rate of production led to the much simpler, cheaper and faster to make Sten submachine gun. The Sten gun was so cheap to make that near the end of World War II, Nazi Germany started manufacturing their own copy of the design (the MP 3008). Britain also used many M1928 Thompsons early on (the interwar period version that could accept a drum magazine), and also many of the improved version M1 (that could only be loaded with a box magazine). After the war, the Sten would be replaced by the Sterling submachine gun.
America and its allies used the Thompson submachine gun, especially the simplified M1 version that was machined not to accept the drum magazine. Because the Thompson was still expensive to produce, the M3 "Grease Gun" was adopted in 1942, followed by the slightly improved M3A1 in 1944. The M3 was not necessarily more effective, but was made primarily of stamped parts and so could be produced with a fraction of the expense and time of the Thompson. It could be configured to fire either .45 ACP ammunition, which the Thompson and M1911 pistol also fired, or the 9 mm Parabellum, widely used by Allies and Axis. It was among the longest serving of the submachine guns designed during the war, being produced into the 1960s and serving in US forces officially into the 1980s.
Finland had developed the M/31 Suomi before the Winter War in which it saw much use. During the Winter war, Finnish ski troops became known for appearing out of woods to a road used by a Soviet column, opening fire with M/31s and disappearing into the woods on the other side of the road, and during the Continuation war the Finnish Sissi patrols would often equip every soldier with M/31s. The weapon fired 9 mm Parabellum rounds from a drum magazine with a capacity of 70 cartridges (although often loaded with up to 74). Although America used box magazines in the Thompson, and Soviet submachine gunners carried only a few drum magazines (usually one drum, if any, and remaining ammunition as box magazines), the Suomi was mostly deployed with drums. They were also less prone to jamming than the box or "casket" magazines developed for the weapon. The weapon was used in combat until the end of Lapland war, and in peacetime service to the late 1970s.
By the end of World War II, the Soviet Union had fielded the largest number of submachine guns, such as the PPSh-41, with whole infantry battalions being armed with little else. Even in the hands of conscripted soldiers with minimal training, the volume of fire produced by massed submachine guns could be overwhelming in an urban environment. The German forces formed similar troops of their own in response to this. Key realizations made during World War II, notably the fact that most small-arms engagements occurred within 100 yards (90 meters), and that a high rate of fire was generally more effective than the slower but more accurate fire, (such as provided by bolt-action and semi-automatic rifles) were some of the key causes for the development of the assault rifle.
1950 to present
Submachine guns lend themselves to moderation with suppressors, particularly so in cases where the weapon is loaded with subsonic ammunition. Variants of the Sten and modern-day Heckler & Koch MP5 have been manufactured with integral suppressors, and such weapons are on occasion used by special forces and police units. Both submachine guns and battle rifles were supplanted by the new assault rifles, such as the CAR-15 and Heckler & Koch HK53. Submachine guns are used by special forces and counter-terrorist units operating in urban environments or cramped interior areas, and as defense weapons for air crews, combat vehicle crews, and naval personnel. Though submachine guns still have a strong hold on niche users, due to their advantage in compact size, they are facing competition from carbines and shortened assault rifles. The dominance of submachine guns in law enforcement tactical operations has been diminished by new developments since the 1990s. Factors such as the wide availability of assault rifles and carbines and the increasing use of body armor have combined to limit the appeal of submachine guns to government agencies. Assault rifles and carbines have been supplementing submachine guns in some roles. Assault rifles are not a complete replacement, since they are generally heavier, have greater muzzle blast, more recoil, and may be likely to overpenetrate due to their use of rifle rounds.
During the Apartheid era, the Rhodesian and South African governments supplied some citizens with modified submachine guns which were known as Land Defence Pistols (LDP) such as the Kommando LDP or Sanna 77, loosely based on the Czech CZ Model 25. LDPs sold to civilians were submachine guns capable of semi-automatic fire only, similar to assault pistols.
Also touted as a further evolution of the submachine gun is the personal defense weapon (PDW), a machine pistol-like weapon which fires armor-piercing pistol cartridges. The PDW is similar in operation to submachine guns and is often considered as such. The trend in modern submachine guns had been toward lighter, smaller weapons utilizing plastics to a greater degree.
Legal ownership by civilians
Private ownership of submachine guns is illegal in most nations, but there are a few exceptions, including the following:
Fully automatic submachine guns fall in to the category of prohibited firearms in Canada, and are only able to be legally owned by those who owned them prior to them becoming prohibited. Semi-automatic versions are also generally prohibited by name; however, some models such as the Heckler & Koch USC and Kriss Vector are available as either Restricted or Non-Restricted firearms, dependent on barrel length (semi-automatic rifles with a barrel length of less than 470mm in Canada are considered Restricted firearms, and require registration and an appropriate Restricted firearms license). Magazines designed and manufactured for use in submachine guns must also be limited to 5 rounds to comply with Canadian magazine regulations.
Civilian ownership of submachine guns is regulated by the Ministry of the Interior, which classifies fully automatic submachine guns as Category A (Restricted Firearms and Accessories) under the provisions of Act 119 of 2002. In addition to a valid gun licence, the prospective civilian owner must obtain a Category A Exemption from a local police agency and demonstrate the reason for owning a submachine gun, e.g. a legitimate firearms collection. Semi-automatic submachine guns are classified as Category B firearms which do not require special exception (e.g. Scorpion Evo 3 S1 is semi-automatic version of fully automatic Scorpion Evo 3 A1  submachine gun).
The Firearms Act of 1998 (amended in 2001) outlawed possession of submachine guns by the general public, although licensed collectors in good standing can obtain permits for older submachine guns from the Gaming and Weapons Administration. Police must verify that the collector is able to store the gun securely to discourage theft. Deactivated and replica submachine guns are legal for historical re-enactment and plays.
Malta's gun law, Cap 480 (Arms Act 2005) and the Arms Licensing regulations are closely based on the EU Arms Directive. Automatic weapons fall under Schedule 1 of the Act and are therefore prohibited firearms. However persons who are Licensed as Collectors (Category A) are permitted to acquire and keep automatic firearms provided these were manufactured prior to 1946. Licensed collectors are obliged to provide adequate security for the safe storage of their firearms. Automatic weapons may not be discharged at the range. However owners that are members of recognised re-enactment teams may use their automatic weapons to fire blanks. A special Police permit is issued for each event.
Civilian gun licenses in Pakistan vary considerably in terms of region and class of firearm. Provincial authorities issue licenses for handguns, shotguns and hunting rifles (bolt action only) that are only legal in the province in which they are issued. The Federal Government, through its Interior Ministry, issues licenses similar to those issued by the provincial government but licenses issued by the Federal Government are valid across provincial boundaries and can be carried throughout the country. The Prime Minister has the authority to allow individuals to purchase and possess automatic weapons.
Submachine guns may be owned by civilians as collectors item or by a simple sport shooting license. The licensed owner must be at least 20 years old or older. Compared to semi-automatic guns only require the owner to be at least 18 years old. As a collectors item the license usually does not permit the weapon being fired. With a sport shooting license the weapon may be fired at any time, such as competition or practice. The most common fully automatic sub-machine gun in civilian hands in Sweden is the Carl Gustaf M/45.
Submachine guns may only be owned by licensed collectors, but cannot be fired in full-automatic mode. Civilians may purchase semi-automatic versions of such firearms and bullets.
Civilian ownership of submachine guns is regulated by the Bureau of Alcohol, Tobacco, Firearms and Explosives under the provisions of the National Firearms Act of 1934 as amended by Title II of the Gun Control Act of 1968. In addition, the Firearms Owners' Protection Act of 1986 outlawed the manufacture of submachine guns for the civilian market and currently limits legal ownership to units produced and properly registered with the BATFE before May 1986. Some states enforce their own laws regulating or forbidding civilian possession of submachine guns. Civilians may purchase semi-automatic versions of such firearms without requiring NFA clearance, although some states (including California and New Jersey) enforce their own restrictions on such weapons. Submachine guns produced after 1986, or not registered before the deadline, can be owned by law enforcement, security agencies, and holders of appropriate FFLs, such as a class 2 or 3 FFL, though those with an FFL do not technically own their weapon; it is a demo weapon that they must relinquish after surrendering their license.
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