In tactical and law enforcement medicine, it is of utmost importance for medical personnel to understand the weapon systems deployed by LEOs and SWAT operators. Not only does this information allow one to render a weapon safe and provide medical care, but it could also be used to protect patients or teammates should the need arise. Of the four primary types of firearms used by LEOs — handguns, long guns, rifles, and submachine guns — the submachine gun stands alone in its use for certain tactical applications.
A submachine gun is a magazine-fed, selective-fire automatic carbine designed to fire handgun cartridges. The term came into popular use with John Thompson—the inventor of the Thompson submachine gun—for his design of an automatic firearm which should be of reduced power in comparison to a machine gun. By strict definition, a machine gun is supposed to fire ordinary-sized rifle cartridges, while a submachine gun is a compact, selective-fire weapon designed for patrol, defense, and concealment, taking pistol ammunition such as 9 mm, 10 mm, or .45 ACP.
Initial designs for this submachine gun date from World War I and were first conceived as a close-quarter offensive weapon, primarily for trench raiding. It reached its zenith during World War II, during which time millions were produced for assault troops and auxiliaries tasked with close-quarter suppressive fire. New designs remained to be developed during the Cold War period, especially in special forces, covert operation commandos, and mechanized infantrymen. Specialized variants were made extremely compact or exceptionally quiet.
The working internals of these submachine guns would differ internally as they do in the model. Some are open-bolt firearms, others are recoil-driven, and still, some are on principles like the roller-delay system. Management of the weapon and loading, unloading, and maintenance could demand extra training from personnel already used to the use of other weapons.
In America, submachine guns have, in various instances, been associated with organized crime and violence, even if most of that was media portrayal. Their use by the Chicago Outfit and infamous bank robbers during the 1920s and 30s, with Thompson submachine guns, coupled with depictions from Hollywood, really set this stereotype in people’s minds.
Because of these shortcomings, the use of submachine guns declined among the frontline infantry during the 1980s and 1990s. By the early 21st century, they had largely been replaced by assault rifles firing rifle rounds in short, rimless cases, most notably the 5.56 NATO/.223 caliber bullet, which has an effective range nearly five times greater than the average pistol round and which can penetrate body armor.
Nevertheless, security forces, police tactical units, or personal guards still use these submachine guns to respond in close quarters because of their weapons’ compact size and ease of control. Here, pistol-caliber ammunition is quiet and, despite producing less recoil and muzzle blast, is extremely useful in close quarters. These advantages get further enhanced by the applicability of suppressors to the respective weapon systems, thus clearly establishing the importance of SMGs in dynamic entries, rapid clearing of rooms, and particular protection tasks.
Naming Conventions and Variants
There is a bit of inconsistency in the classification of submachine guns, with British Commonwealth sources at different times classing SMGs as “machine carbines,” while other sources sometimes refer to them as “machine pistols.” More broadly, the latter term is also applied categorically to any handgun-style firearm capable of fully- or burst-automatic fire, such as the Beretta 93R, Glock 18, or H&K VP70. More recently, intermediate-caliber weapons like the FN P90 and H&K MP7 have come to be referred to in common parlance as submachine guns; in contrast, much earlier, short-barreled assault rifles, such as the CAR-15, H&K53, and Mk18, also came to be referred to as submachine guns for their analogous functions.
Firearms that are visually nearly identical to an SMG but are semiautomatic-fire-only became a favorite with civilians; in a general sense, these are referred to as “pistol-caliber carbines.” Due to length restrictions under the NFA, these generally have longer barrels or lack a shoulder stock concerning their military or law enforcement versions. A very limited number of fully automatic SMGs are transferable as NFA items for civilian ownership, provided they were manufactured and registered before 1986.
SWAT team commonly employs an MP5 made by H&K or a UMP by H&K, an APC9 by B&T, and an FN P90. The features of the SMG and its design are popular for being very reliable and accurate with reduced recoil, ease of handling owing to its compact size, and other convenience features.
- H&K MP5: Long lauded for its accuracy, low recoil, and modularity of design, the MP5 is an absolute standard within the SWAT arsenal across the globe. The K version is boundlessly concealable, and the SD model is singularly well-muffled.
- H&K UMP: The UMP is the modern successor to the modularity and innovation of the MP5 and is available in multiple calibers, making it easy for an agency to field an SMG in whatever pistol caliber they prefer.
- B&T APC9: In 2019, this sub-compact weapon became the army of the U.S.A.’s official sub-compact weapon. The weapons are available in different configurations, including ones compatible with lots of the common-duty weapon magazines.
- FN P90: Innovation in design and a high-capacity magazine are two of the leading facts this weapon model is famous for. The P90 is chambered in 5.7x28mm, which is a high-velocity, small-caliber cartridge designed to increase performance against threats wearing soft body armor.
SWAT teams are around to ensure the public’s safety at venues that strongly suggest massive danger if not heeded. The use of submachine guns is only one of the elements of their training and equipment. The selection of submachine guns is based on their suitability for close-quarters combat and the specific requirements of the mission. As law enforcement tactics and technology continue to evolve, SWAT teams will adapt their training and equipment accordingly. All tactical medical personnel should be familiar with and proficient in the use of pistols, shotguns, rifles, submachine guns, and other weapon systems.