The Trench Broom's Tale: A Brief History of the Submachine Gun

The submachine gun is a paradox, a weapon born of industrial might yet designed for the most primal, intimate form of combat. It is a compact, fully automatic firearm engineered to fire pistol-caliber ammunition. This seemingly simple definition belies its revolutionary nature. Before its arrival, the battlefield was dominated by two extremes: the slow-firing, long-range precision of the bolt-action Rifle and the cumbersome, emplacement-bound fury of the heavy Machine Gun. The submachine gun, or SMG, carved out a new tactical niche between them. It sacrificed the rifle’s range and power for something far more valuable in the claustrophobic chaos of modern warfare: overwhelming, controllable, close-quarters firepower. It is not an assault rifle, which fires a more powerful intermediate cartridge, nor a pistol, which lacks its sustained automatic fire. The SMG is a unique instrument, a handheld storm of lead conceived in the mud of the trenches, glamorized in the speakeasies of Prohibition, democratized in the crucible of a world war, and ultimately refined into a tool of surgical precision for the shadow warriors of the modern age. Its story is the story of the 20th century's changing face of conflict.

The story of the submachine gun begins not in a designer’s workshop, but in the hellscape of the Western Front during Trench Warfare. By 1915, the war of movement had bled into a static nightmare of parallel ditches stretching from the Swiss border to the North Sea. Here, the traditional tools of infantry were tragically mismatched to the task at hand. The standard-issue bolt-action rifle, a superb weapon for open-field engagements at 500 meters, became a clumsy, unwieldy spear in the narrow, winding confines of a trench. Its low rate of fire was a death sentence when a dozen enemy soldiers appeared around a corner just feet away. At the other end of the spectrum, the heavy machine gun was the undisputed king of no-man's-land, a defensive god that could scythe down hundreds in minutes. But it was a fortress unto itself—heavy, water-cooled, and requiring a crew of several men to operate. It could not lead an attack. This created a deadly tactical vacuum. The most terrifying moment for a soldier was the trench raid—a brutal, close-quarters affair of storming the enemy's position with grenades, clubs, knives, and pistols. Military planners on all sides desperately sought a weapon that could bridge the gap, a “trench broom” that could sweep the enemy from their subterranean burrows. The ideal weapon needed to be:

• Portable: Light enough for a single soldier to carry and fight with while moving.
• Compact: Short enough to be maneuvered easily in the tight confines of a trench.
• High-Volume Fire: Capable of spitting out a stream of bullets to suppress or eliminate multiple targets in seconds.

The technological ingredients were simmering. Hiram Maxim had already perfected the principles of automatic fire decades earlier. Pistol cartridges, while weak, were small, light, and produced manageable recoil, making them suitable for a lightweight, handheld automatic weapon. The first true glimmer of the concept appeared in Italy with the Villar Perosa. Developed in 1915, this odd-looking device was essentially two small, barreled automatic mechanisms bolted together, firing 9mm pistol ammunition. However, the Italian military failed to grasp its true potential, issuing it with a shield and bipod as a static, defensive “light” machine gun, a role for which its pistol cartridges were far too weak. The idea was sound, but its tactical application was misguided. The weapon was a solution, but it had been applied to the wrong problem. The true birth of the submachine gun awaited a nation that would pair the concept with the correct combat doctrine: Germany.

As the Great War entered its final, desperate phase, the German High Command developed a new and terrifying tactical doctrine: the Sturmtruppen, or Storm Troopers. These were elite infiltration units, bypassing strongpoints to strike deep into the enemy’s rear, sowing chaos and collapsing the front line from within. They were specialists in lightning-fast, violent, close-range combat. They needed a new kind of weapon to match their new kind of warfare. The answer came from the drawing board of a brilliant gun designer named Hugo Schmeisser, working for the Bergmann Waffenfabrik. His creation, the Maschinenpistole 18, or MP 18, was the world's first practical submachine gun. It was a masterpiece of wartime pragmatism. It was not a finely crafted dueling pistol; it was a brutal tool for a brutal job. The core of its design was the simple blowback mechanism. This was a stroke of genius in its simplicity. To understand it, imagine a firearm with no complex locking system. When a cartridge is fired, the explosive force of the propellant pushes the bullet down the barrel and, simultaneously, pushes the cartridge case backward. In a simple blowback design, this backward force is all that is needed to cycle the action. The mass of the bolt and the tension of a spring are carefully calculated to be just heavy and strong enough to keep the breech sealed until the bullet has left the barrel and pressure has dropped to safe levels. The bolt then flies backward, ejects the spent casing, and is pushed forward again by the spring, stripping a new round from the magazine and chambering it. If the trigger remains pulled, it fires again immediately. This “open-bolt” design (where the bolt remains to the rear when ready to fire) was simple to manufacture and incredibly reliable, making it perfect for the mud-soaked conditions of the trenches. The MP 18 was chambered for the 9mm Parabellum pistol round and fed from a 32-round “snail” drum magazine originally designed for the Luger Pistol. It was relatively heavy, but it could unleash a torrent of fire at a rate of over 500 rounds per minute. In the hands of the Sturmtruppen during the 1918 Spring Offensive, it was devastating. A single soldier armed with an MP 18 could lay down a base of fire that previously required a whole team, overwhelming defenders in a hail of lead. While it was produced too late and in too few numbers to change the outcome of the war, the MP 18 had proven the concept. A new class of weapon had been born, forged in the crucible of industrial warfare's most savage fighting. The age of the submachine gun had begun.

The Treaty of Versailles, intended to declaw the German military, specifically banned the production and possession of submachine guns. But the genie was out of the bottle. The idea of a personal automatic weapon had taken root, and its most iconic incarnation would emerge not on a European battlefield, but on the crime-ridden streets of Prohibition-era America.

Brigadier General John T. Thompson was another man obsessed with the idea of a “trench broom.” He envisioned a handheld machine gun for the American Doughboys, but his weapon, the Thompson Submachine Gun, was perfected just too late to see service in World War I. His “Annihilator,” as he first called it, was a different beast from the MP 18. Where the German gun was simple, the Thompson was a beautifully machined, complex, and expensive piece of industrial art. It used a sophisticated and costly “Blish Lock” delayed-blowback system, featured fine wood furniture, and was chambered in the powerful .45 ACP pistol cartridge. With no military contracts, Thompson's Auto-Ordnance Corporation turned to the civilian and police markets. It was here that the “Tommy Gun” found its notorious fame. In an era of rampant organized crime fueled by the illegal liquor trade, the Thompson became the weapon of choice for gangsters like Al Capone, who valued its terrifying firepower for ambushes and assassinations. The sound of its distinctive, chattering report earned it the moniker “Chicago Typewriter.” The image of a gangster in a pinstripe suit, violin case in hand—not for a musical instrument, but for a disassembled Tommy Gun—became seared into the American cultural consciousness. Law enforcement, initially outgunned, soon adopted the Thompson themselves, leading to legendary shootouts between G-Men and bank robbers across the Midwest. The Thompson submachine gun became a potent symbol, representing both the breakdown of law and order and the federal government's struggle to restore it.

While the Tommy Gun dominated the headlines, the submachine gun concept was quietly evolving worldwide. Designers in other nations, unburdened by the Thompson's cost and complexity, followed the German model of simplicity and pragmatism.

• In Finland, Aimo Lahti developed the Suomi KP/-31, a superbly accurate and reliable SMG known for its high quality. Its 71-round drum magazine and rugged design would prove devastatingly effective against the invading Soviets in the Winter War of 1939-40 and would heavily influence the design of a future Soviet icon.
• Italy, home of the proto-SMG Villar Perosa, continued to innovate. The Beretta company produced a series of well-regarded submachine guns, starting with the Model 1918.
• Even in Germany, clandestine development continued, laying the groundwork for the weapon that would define the German soldier in the next great conflict.

The submachine gun was no longer a niche weapon. It had become a tool for paramilitaries, police forces, and criminals alike. It was the weapon of the ambush, the raid, and the rebellion. Its journey through the turbulent interwar period had transformed it from a military tool into a cultural icon, setting the stage for its ultimate test.

World War II was the submachine gun's golden age. The conflict was a “total war” that demanded the mobilization of entire societies and the production of weapons on an unprecedented scale. The lightning-fast armored warfare of the Blitzkrieg and the brutal, block-by-block urban combat on the Eastern Front created a near-insatiable demand for a compact, automatic weapon. The era of the finely machined, expensive SMG was over. The new philosophy was one of expediency and mass production. The victor would not be the nation with the best submachine gun, but the nation that could put a good enough submachine gun into the hands of millions of soldiers.

The German MP 40 is perhaps the most iconic submachine gun of the war, often mistakenly called the “Schmeisser” (Hugo Schmeisser had no part in its design). It was the epitome of German industrial efficiency. Gone was the wooden stock of the MP 18, replaced by a folding metal stock. Gone were the expensively milled parts, replaced by stamped metal components and a Bakelite plastic grip. This was a weapon designed not by artisans, but by production engineers. It was cheap to make, quick to assemble, and perfectly suited for its intended users: panzer crews, paratroopers, and squad leaders. While its relatively slow rate of fire made it highly controllable, its image, slung around the neck of a German soldier, became a fearsome symbol of the Nazi war machine.

The Allied powers responded with their own marvels of wartime production, each reflecting a unique national character.

• Great Britain's Sten Gun: Facing imminent invasion in 1940 and having lost much of its equipment at Dunkirk, Britain needed a submachine gun immediately. The answer was the Sten. It was brutally, almost comically, simple. Made from little more than a steel tube, a spring, and a handful of stamped parts, it looked like a piece of plumbing. Early models were crude and prone to accidental discharge, but they worked. Crucially, a Sten gun could be manufactured for about $10 (less than a fifth of the cost of a Thompson at the time) in small workshops all across the country. It was the ultimate expression of wartime desperation and resilience. Ugly, cheap, and produced by the millions, the Sten armed not only the British Tommy but was also air-dropped in vast quantities to resistance movements across occupied Europe, becoming a symbol of clandestine rebellion.
• America's M3 “Grease Gun”: The United States entered the war with the expensive Thompson. While a beloved weapon, it was a production bottleneck. The military demanded a cheaper alternative, and the answer was the M3. Like the Sten, it was a product of stamped metal and production-line thinking. Its telescoping wire stock and utilitarian appearance earned it the nickname “Grease Gun” for its resemblance to the mechanic's tool. While not as iconic as the Thompson, the M3 was a reliable and effective workhorse, produced in huge numbers and serving American soldiers well into the Korean and Vietnam wars.
• The Soviet Union's PPSh-41: Perhaps the ultimate expression of the mass-produced World War II submachine gun was the Soviet PPSh-41, affectionately known as the “Papasha” (daddy). Designed by Georgy Shpagin, it was even simpler to produce than the German MP 40 or the British Sten. It was robust, utterly reliable in the freezing conditions of the Eastern Front, and featured a blistering rate of fire of over 900 rounds per minute. Its most defining feature was a 71-round drum magazine (a direct descendant of the Finnish Suomi's design) that allowed a soldier to spray a seemingly endless stream of bullets. Entire Soviet regiments were armed with nothing but the PPSh-41. In the meat grinder of Stalingrad, where battles were fought room-to-room, the PPSh-41 was the perfect weapon. It became the symbol of the Red Army soldier and the embodiment of the Soviet doctrine of overwhelming firepower through sheer numbers.

During World War II, the submachine gun was democratized. It was no longer a specialist's weapon. It was a people's gun, placed in the hands of conscripts, partisans, and factory workers-turned-soldiers. It changed the sound, feel, and tactics of infantry combat forever.

In the ashes of World War II, the seeds of the submachine gun's obsolescence had already been sown. Ironically, the innovation that would dethrone it came from its most prolific user: Germany. During the war, German engineers had developed a new type of weapon, the Sturmgewehr 44 (StG 44), which fired a new type of ammunition. This was the “intermediate cartridge”—more powerful than a pistol round but less powerful than a full-sized rifle round. This concept was revolutionary. The Assault Rifle, as this new class of weapon came to be known, offered the best of both worlds. It had a long-enough effective range (300-400 meters) to replace the bolt-action or semi-automatic battle rifle in most infantry engagements, while still offering the controllable, high-volume automatic fire that had made the submachine gun so valuable. The post-war world quickly embraced this new paradigm. The Soviet Union, deeply impressed by the StG 44, developed the single most influential firearm in history: the AK-47. The United States eventually responded with the M16. These assault rifles became the new standard for infantrymen worldwide. The submachine gun, with its anemic pistol cartridge, was now out-ranged and out-powered on the open battlefield. Its role as the primary weapon of the common soldier was over. It was relegated to vehicle crews, rear-echelon troops, and second-line forces. The golden age of the trench broom had come to an end.

Just as it seemed destined for the museum, the submachine gun found a new calling. As the Cold War simmered and the world grappled with terrorism, hijacking, and hostage crises, a need arose for a different kind of weapon. The battlefield was no longer just a field; it was the aisle of an airplane, a school hallway, or an embassy corridor. In these high-stakes, close-quarters environments, the full power and range of an assault rifle were a liability. Its bullets could easily over-penetrate, harming hostages or bystanders on the other side of a wall. This was the perfect niche for a reborn submachine gun. A new generation of SMGs emerged, prioritizing not mass production, but precision, control, and compactness. The undisputed king of this new era is the Heckler & Koch MP5. Introduced in the 1960s, the German-made MP5 was a quantum leap in SMG design. Unlike its World War II ancestors that used a simple open-bolt system, the MP5 used a sophisticated roller-delayed blowback mechanism derived from a battle rifle. Firing from a “closed bolt” (where the bolt is already forward when the trigger is pulled), it offered surgical accuracy previously unheard of in a submachine gun. It was compact, incredibly reliable, and controllable. The MP5's moment in the global spotlight came in 1980, when British SAS commandos, clad in black and armed with MP5s, stormed the Iranian Embassy in London to end a hostage crisis—all on live television. The event cemented the MP5's reputation as the elite weapon of the world's premier counter-terrorist and special operations forces. From the US Navy SEALs to Germany's GSG 9, the MP5 became the tool of the modern shadow warrior. This evolution continued, blurring the lines of classification. The Israeli Uzi, another post-war design, became an icon of the 1980s with its “telescoping bolt” design that made it extraordinarily compact. In the 1990s, the concept of the Personal Defense Weapon (PDW) emerged with firearms like the FN P90. These weapons fired small-caliber, high-velocity rounds designed specifically to defeat modern body armor, a task for which traditional pistol cartridges were ill-suited. Even in its specialized twilight, the submachine gun's cultural footprint remains immense. It is a staple of action movies and video games, its silhouette instantly recognizable. Depending on the model, it can evoke the gangster, the commando, the terrorist, or the hero. It is a cultural artifact as much as a military one.

The journey of the submachine gun is a microcosm of the 20th century's violent history. It was born from the industrial slaughter of the trenches, a desperate technological fix for a tactical nightmare. It came of age on the lawless streets of America, becoming a symbol of glamour and fear. It reached its zenith in a global conflict that demanded millions of cheap, effective weapons for a new kind of mobile and urban warfare. It was nearly cast into obsolescence by a superior technology, only to be reborn as a specialized instrument of precision for an age of asymmetric conflict. The submachine gun is a testament to a simple, brutal truth of human conflict: the fight is often won or lost at arm's length. From the Sturmtruppen clearing a French trench to the SWAT officer breaching a door, the need for a compact, controllable volume of fire has remained a constant. The trench broom, in all its forms, has been the answer. It is more than just a collection of metal and springs; it is a story of innovation born of necessity, a cultural icon, and an enduring piece of our turbulent modern history.