MP 18: The Maschinenpistole That Invented a Weapons Class

The Bergmann MP 18—formally designated the Maschinenpistole 18/I—is a German submachine gun designed by Hugo Schmeisser and manufactured by Bergmann Waffenfabrik. Introduced into German Army service in 1918 during the final stages of World War I, it was purpose-built for the Sturmtruppen, the assault groups tasked with clearing enemy trenches at close range. The weapon gave individual infantrymen a volume of fire that no pistol or rifle could match in those confined, chaotic conditions.

Production was relatively short-lived, ending shortly after the war, but the MP 18's influence stretched across four decades of firearms development. According to the Library of Congress, the Bergmann weapons "influenced the development of later German and other nations' submachine guns," including:

• British Lanchester, Sten and Sterling
• Soviet PPSh-41
• Finnish Suomi KP/31
• Italian Beretta Model 38
• Japanese Type 100

That is a remarkable lineage for a gun that saw only a few months of actual combat.

The question of whether the MP 18 was the first submachine gun is legitimately debated. The Italian Villar Perosa preceded it, and the Austro-Hungarian Maschinengewehr Hellriegel was trialed as early as October 1915.

The MP 18 was the first mass-produced submachine gun to be fielded extensively in an infantry assault role—and that distinction is what made it the template everything else followed.

What is not debated is that the MP 18 earned this distinction through its scale and form factor that everyone else could learn from.

The 1915 Requirements

The story starts in 1915, when the German Rifle Testing Commission at Spandau recognized that existing weapons were wrong for the problem. Trench combat happened at ranges measured in feet, not yards. Attempts to modify the Luger and Mauser C96 pistols to fire automatically failed—those pistols were too light, and their cyclic rates of around 1,200 rounds per minute made aimed fire impossible.

The commission concluded that a completely new weapon class was needed: something that fired pistol-caliber ammunition but was designed from the ground up for fully automatic fire.

Schmeisser's Solution

Theodor Bergmann, working with a small team that included Schmeisser, took on the requirement. Hugo Schmeisser had already developed blowback systems for Bergmann pistols and applied the same principle to a larger, shoulder-fired platform. The wooden stock and rifle-style body gave the shooter control that no pistol-framed automatic could offer.

A perforated barrel jacket managed heat from sustained automatic fire. The receiver was machined from thick steel tube—around 3mm wall thickness, which was heavier than later designs but robust. The bolt itself was machined from a single block of steel.

Four versions were evaluated by the German Army—the MP 18/I, II, III, and IV—differing primarily in their feed systems.

The Magazine Decision

The MP 18/I, the version that went into production, was designed to use the TM 08 Trommelmagazin, the 32-round snail drum magazine already in service with the long-barreled artillery Luger. Schmeisser had originally designed a 20-round box magazine for the weapon, but the testing commission overruled him. That decision would cause headaches in the field. The snail drum was heavy, awkward, required a proprietary loading tool, and needed a special sleeve adapter to seat properly in the MP 18's magazine well.

Full-scale production began in early 1918.

Operating Mechanism

The MP 18 operates on a straightforward open-bolt blowback principle. When the trigger is pulled, the bolt travels forward under spring pressure, strips a round from the magazine, chambers it, and fires—all in one motion. There is no locked breech; the cartridge case itself seals the chamber during firing, and the bolt's mass and the return spring handle the rest. It is mechanically simple, which is part of why the design proved so durable and so widely copied.

Specifications

The weapon fires the 9×19mm Parabellum cartridge, the same round used in the Luger. Export variants of later evolutions chambered 7.63×25mm Mauser, 7.65×21mm Parabellum, and other calibers. Muzzle velocity is 380 m/s (1,247 ft/s), and cyclic rate of fire runs approximately 350–500 rounds per minute—slow enough by later standards that a trained shooter could manage short bursts with trigger discipline. The MP 18 had no semi-automatic selector; it fired fully automatic only.

Overall length is 832mm (32.8 inches) with a 200mm (7.9-inch) barrel. Loaded weight with the TM 08 drum pushed the gun over 5 kg (11 lb)—heavy for a weapon of its size, a direct consequence of the thick receiver walls and all-machined construction. Sights are a basic V-notch rear and front post, calibrated for the short engagement ranges the weapon was designed for.

Safety Concerns

One significant engineering liability: the MP 18 had no external safety. Like many open-bolt designs, a hard knock to the buttstock while the bolt was in the forward position could cause an accidental discharge—the impact could drive the bolt rearward far enough to pick up and chamber a round. Soldiers compounded the risk by habitually leaving the bolt closed to keep debris out of the chamber.

German police, who received the guns in large numbers after the war, specifically requested external safeties, and bolt-locking safeties were subsequently added to police-issue weapons. Later submachine guns—the Sten and MP 40 among them—addressed this by allowing the cocking handle to lock into the receiver tube.

After 1920, the MP 18 was modified to accept straight box magazines rather than the snail drum, a change that substantially improved handling and reliability.

Late War Deployment

The MP 18's actual combat record in World War I is narrower than its reputation suggests. Contrary to a persistent claim, according to Wikipedia there is "no concrete evidence that the Bergmann MP 18/I reached the front lines in early 1918 or that submachine guns were employed by German Sturmtruppen during the Spring Offensive." The weapon was primarily fielded in the second half of 1918 as the war was collapsing around Germany.

The first documented unit to receive the MP 18 was the 237th Infantry Brigade of the 119th Infantry Division, which took delivery of 216 guns for field trials in July 1918—after the Spring Offensive had already ended. Shortly after, the MP 18 appeared at the Battle of Amiens. Canadian troops of the 13th Battalion, 5th Regiment Royal Highlanders of Canada were photographed with a captured MP 18 on August 11, 1918.

Production Numbers Debate

How many guns actually made it to combat is genuinely murky. Major-General Ernst von Wrisberg, director of the Prussian War Ministry, wrote that approximately 17,000 guns had been delivered by October 1918, a figure consistent with surviving military acceptance stamps. Existing serial numbers reach into the 30,000 range.

A French post-war report claimed Germany produced 50,000 units in 1918, with only 8,000–10,000 delivered. The best evidence—the serial number ranges of guns captured by the Allies—suggests the number that actually reached the front was far lower, with a reasonable estimate around 4,000 guns seeing combat.

The Army's intent had been to issue six MP 18s per company with a dedicated ammunition carrier. That never materialized at scale. The combination of late delivery, feed mechanism problems with the snail drum, and the collapse of the German war effort meant the MP 18's WWI combat service was brief and limited in scope.

Post-War Proliferation

Post-armistice, the guns proliferated in ways nobody planned. The Freikorps—paramilitary veterans' units—armed themselves from military depots and used MP 18s extensively during the Spartacist uprising and other internal German conflicts. The Weimar government worked alongside the Freikorps to suppress the uprising and did little initially to restrict access.

Eventually, surviving MP 18s were formally allocated to police forces, particularly the Sicherheitspolizei, stamped "1920" to indicate government-approved issue. Many of the estimated 50,000 produced fell outside official channels entirely—into paramilitary hands, criminal organizations, and eventually foreign buyers.

In 1922, Foreign Minister Walther Rathenau was assassinated by ultranationalists using a stolen MP 18. The gun was making its presence felt in European politics well beyond the trenches it was designed for.

The MP 18 showed up in conflict after conflict through the interwar years:

• The Chaco War in South America
• The Spanish Civil War
• China's Warlord Era and Second Sino-Japanese War
• The 1924 Estonian coup attempt
• WWII service with Sicherheitsdienst and Waffen-SS

The 1924 Estonian coup attempt saw MP 18s reportedly used to defend the Tallinn barracks against Communist militants armed with Thompson submachine guns—possibly the first engagement where submachine guns appeared on both sides. The Third Reich distributed old MP 18 stocks as foreign aid to aligned fascist groups in France, Austria, and Czechoslovakia, and the gun saw limited WWII service with the Sicherheitsdienst, eastern Waffen-SS foreign divisions, and Kriegsmarine coastal artillery units.

International Licensing

Bergmann sold the MP 18's manufacturing license to SIG of Switzerland, which produced it as the SIG Bergmann 1920 in .30 Luger and 7.63mm Mauser. From that single licensing deal, the design scattered across the world.

China produced copies at multiple factories—Tsing Tao, Dagu, and Hanyang—with each facility producing its own variant. The Tsing Tao version used a bottom-mounted magazine and was manufactured in large numbers for Chinese Republican forces from the mid-1920s through the 1940s. Japan's navy ordered 125 SIG Bergmanns in 1922 and 320 more in 1929, fitting them with Type 30 bayonets for Marine use.

Finland purchased 1,523 SIG M/20s between 1922 and 1940. Estonia produced the Arsenal M23 based on the SIG Bergmann, chambered in 9mm Browning Long. In the United States, Chicago dealer Vincent Daniels imported 7.65mm SIG Bergmanns, added a fire selector, and sold them as "Daniels Rapid-Fire Carbines"—which were purchased by members of the Northside Gang and the Chicago Outfit.

The Schmeisser Evolution

Hugo Schmeisser, working independently at C.G. Haenel in the mid-1920s, developed a series of prototypes designated the MP Schmeisser, which added a push-button fire selector above the trigger group for semi-automatic capability—something the original MP 18 lacked. After testing by the Reichswehr in 1925 produced no adoption decision, Schmeisser continued refining the design.

By the late 1920s this had evolved into the MP 28/II, which introduced a new double-stack Schmeisser-designed magazine. Exported through Belgian manufacturer Pieper to sidestep Treaty of Versailles restrictions, these weapons—despite carrying Belgian assembly markings—were manufactured at Haenel and shipped to Pieper for final assembly. Once the Nazis came to power in 1933 and the Inter-Allied Commission of Control stopped enforcing Versailles, Haenel openly stamped these guns MP 28/II.

Global Derivatives

The MP 28 was copied by the Second Spanish Republic as the Avispero, chambered in 9mm Largo with a 36-round magazine. France developed the Pistolet Mitrailleur Modèle 1924 (STA) directly from captured MP 18s, adopting it on August 11, 1925, though the program eventually collapsed after only 1,000 of an 8,000-gun order were delivered.

Britain copied the MP 28 directly in 1940 to produce the Lanchester for the Royal Navy—brass magazine well, bayonet mount, and all—specifically because the Lanchester's bolt and magazine were interchangeable with the MP 28's. The Sten borrowed the side-mounted magazine and simplified open-bolt system from the same lineage.

The SIG Bergmann 1920's influence pushed further east. According to Wikipedia, it "was the inspiration for the Estonian Tallinn 1923, the Japanese Type 100 submachine gun and the Finnish Suomi model 31, which in turn inspired Degtyarev for his PPD-34." That chain runs from Bergmann's Suhl factory through Helsinki to Moscow—the MP 18's mechanical DNA running through weapons that fought on opposite sides of the Eastern Front.

Ironically, Hugo Schmeisser's name became popularly attached to the MP 40—a weapon he had minimal involvement in designing—largely because the German War Office mandated that the MP 40 use a magazine design Schmeisser had patented for the MP 18 and MP 28. His actual contribution to the submachine gun, the MP 18 itself, is less associated with his name in popular memory.

The MP 18 is one of those weapons where the historical weight is almost out of proportion to what it actually did in combat. It fired for maybe four months in WWI, in limited numbers, against a collapsing enemy. And then it spent the next four decades showing up in every conflict on earth and fathering most of the significant submachine gun designs of the 20th century.

What Schmeisser got right—the open-bolt blowback system, the shoulder-fired wooden stock, the pistol-caliber cartridge—turned out to be so mechanically sensible that designers kept copying it until polymer and stamped steel changed the economics of the whole enterprise.

The Sten was essentially the MP 18's philosophy taken to its logical wartime extreme: make it simpler, make it cheaper, keep the same operating principle.

The snail drum magazine is the one part of this story that reads as a cautionary tale. Schmeisser designed a perfectly serviceable box magazine, and the testing commission overruled him in favor of a heavy, complicated drum that caused stoppages in the field. That kind of institutional second-guessing of the actual designer is a pattern that repeats throughout firearms history, and the MP 18 is one of the cleaner examples of it—the magazine was changed out after the war, and the gun got noticeably better.

The Treaty of Versailles chapter is also worth paying attention to, because it keeps getting simplified into mythology. The treaty didn't ban the MP 18. It restricted Germany to 1,134 such weapons—low enough to be effectively hobbling, but not an outright prohibition. The claim that it was banned outright is repeated constantly and is simply wrong. Schmeisser kept working, Haenel kept manufacturing through export arrangements, and by 1933 the restrictions were a dead letter anyway.

If you're tracing the line from the first enclosed cartridge to the AK-47, the MP 18 is one of the cleaner milestones on that path—not because it was perfect, but because it was first at scale and first in a form that everyone else could actually learn from.

• Wikipedia: MP 18
• MilitaryFactory.com: Bergmann MP18/I
• Firearms History, Technology & Development: The MP 18 Submachine Gun
• Library of Congress: From the Submachine Gun to the Assault Rifle
• NRA Museums: Bergmann 'Machine Pistol'
• Smithsonian: MP 18/1 Submachine Gun

Last Updated: February 27, 2026