Thompson submachine gun
The Thompson submachine gun is a blowback-operated, selective-fire submachine gun invented by U.S. Army Brigadier General John T. Thompson and first produced by the Auto-Ordnance Corporation in 1919.[1][2] Designed as a "trench broom" to provide one-man automatic fire support in World War I close-quarters combat, it chambers the .45 ACP pistol cartridge, utilizes detachable box or drum magazines, and weighs approximately 10 pounds (4.5 kg) unloaded with an 11.5-inch barrel.[3][4] Though arriving too late for widespread use in the Great War, the weapon—nicknamed the "Tommy Gun"—achieved notoriety in the hands of Prohibition-era gangsters and law enforcement in the 1920s and 1930s due to its high rate of fire and distinctive silhouette.[5][6] Adopted by the U.S. military in 1940, simplified variants like the M1 and M1A1 saw extensive service with Allied forces during World War II, particularly by paratroopers, Marines in Pacific jungle fighting, and commandos for its reliability in suppressive fire roles, with over 1.5 million units produced by war's end.[7][8]
Development
Origins and Design Concept
John Taliaferro Thompson, a retired U.S. Army brigadier general and ordnance expert born in 1860, conceived the submachine gun concept in 1915–1916 amid the stalemate of World War I trench warfare.[5] As a West Point graduate (class of 1882) who had supervised development of the M1903 Springfield rifle and influenced adoption of the .45 ACP cartridge, Thompson sought to bridge the firepower gap between pistols and rifles with a lightweight, shoulder-fired automatic weapon for individual infantry use.[9] He termed the weapon a "Trench Broom," intended to sweep enemy positions in close-quarters combat with rapid bursts, drawing inspiration from European automatic designs but prioritizing simplicity and portability for American forces.[10] To realize this vision, Thompson founded the Auto-Ordnance Corporation in 1916, securing financial backing from New York businessman Thomas Fortune Ryan to fund research and development.[5] The core design principle emphasized selective-fire capability using the .45 ACP pistol round, selected for its proven stopping power in trenches while enabling controllable full-automatic fire without excessive recoil, unlike rifle cartridges.[10] Thompson coined the term "submachine gun" to describe the weapon, distinguishing it from heavier machine guns by its use of handgun ammunition in a compact, rifle-like platform.[9] The initial mechanism relied on John Blish's 1915 patent for a delayed blowback system, employing a bronze H-shaped lock and wedge to exploit friction for safe cycling with the relatively low-pressure .45 ACP, allowing reliable operation at rates exceeding 600 rounds per minute without complex gas or recoil systems.[5] This approach aimed for mechanical simplicity and rapid production potential, though prototypes like the 1918 Annihilator emerged too late for World War I deployment.[10] The concept prioritized suppressive fire for assaulting fortified positions, reflecting causal realism in adapting to static warfare's demands for volume over precision at short ranges.[9]Early Prototypes and Testing
The initial prototype of the Thompson submachine gun, dubbed the "Persuader," was completed in late 1917 as an experimental effort to create a compact, high-rate-of-fire weapon for trench warfare, featuring a belt-fed mechanism that bore little resemblance to production models.[11] Approximately 40 prototypes followed through 1919, incorporating iterative refinements to the delayed blowback system based on Theodore Blish's 1915 patent, which aimed to lock the bolt via metallic friction under pressure, though subsequent analysis revealed the design functioned primarily as simple blowback.[11] [5] These early models, including the Model of 1919 in .45 ACP caliber with optional box magazines, emphasized a rear pistol grip integrated near the receiver and a firing pin integrated into the actuator's extremity, achieving a cyclic rate of around 1,000 rounds per minute.[5] On April 27, 1920, the U.S. Army conducted preliminary functioning tests at Springfield Armory using a Model 1919 prototype, firing 2,000 rounds with only one stoppage, demonstrating reliable operation under controlled conditions.[5] [12] Later in 1920, the U.S. Marine Corps performed similar endurance tests, yielding comparable results with minimal malfunctions, though both services declined to recommend adoption, citing factors such as high unit cost, excessive weight relative to output, and lack of tactical necessity in post-World War I doctrine.[5] These evaluations highlighted the weapon's mechanical robustness but exposed limitations in practicality for military issue, prompting further private-sector refinements before commercial production commenced in 1921.[12]Initial Production Challenges
The initial production of the Thompson submachine gun faced significant hurdles following the completion of prototypes in 1919. Auto-Ordnance Corporation, formed by John T. Thompson, contracted Colt's Manufacturing Company to produce the Model 1921, with manufacturing commencing in 1921 and resulting in approximately 15,000 units.[13][14] This small-scale output reflected the gun's complex design, which relied on precision-machined steel components and high manufacturing tolerances rather than simpler stamping methods used in later wartime productions.[13] A primary challenge was the exorbitant production cost, priced at $200 per unit—equivalent to roughly $3,000 in contemporary terms—making it prohibitively expensive compared to standard rifles costing $20–$30.[15] This stemmed from the intricate fabrication of parts, including the receiver and bolt assembly, which demanded skilled labor and specialized tooling unsuitable for rapid mass production.[15] Additionally, the Blish lock mechanism, intended as a delayed-blowback system to handle the .45 ACP cartridge, introduced unnecessary complexity; in practice, it provided no effective delay and contributed to wear, jamming risks from residue, and doubts about its efficacy even during pre-production testing in 1917.[16] Early models exhibited an excessively high cyclic rate of around 1,500 rounds per minute, rendering full-automatic fire difficult to control without modifications implemented in subsequent variants.[15] Market reception compounded these technical and economic issues, as the end of World War I in 1918 eliminated the anticipated trench warfare demand that had driven the design.[13] With no steady military buyers, sales were confined to limited purchases by entities such as the U.S. Marine Corps for "banana wars" interventions, the U.S. Postal Inspection Service, select police departments, and sporadic international clients, marking the gun as a commercial failure in its debut decade.[15][13] These factors delayed broader adoption until criminal notoriety and renewed global conflict spurred demand.[17]Production History
Pre-World War II Models
The first production model of the Thompson submachine gun was the Model of 1921, with manufacturing beginning in 1921 under contract with Colt's Patent Fire Arms Manufacturing Company for the Auto-Ordnance Corporation. Approximately 15,000 units were produced by Colt between 1921 and 1922.[18] This model was chambered for the .45 ACP cartridge, operated via delayed blowback using the Blish principle, and offered select-fire capability with a cyclic rate of around 850 rounds per minute.[3] It weighed 10.75 pounds unloaded, featured a 10.5-inch barrel, and accepted 20- or 30-round box magazines as well as 50- or 100-round drum magazines.[19] The design included a vertical foregrip, wooden pistol grip stock, and provisions for iron sights. Variants of the Model 1921 included the 1921AC, introduced circa 1926, which added a Cutts compensator—a muzzle device with adjustable ports—to mitigate muzzle rise during full-automatic fire.[3] Another subvariant, the Model 1923, was configured for U.S. military trials with a lengthened 14.5-inch barrel, bipod, and horizontal foregrip to enhance stability and evaluate infantry applications.[18] These early guns were marketed to law enforcement, civilians, and foreign entities, though sales were constrained by the unit cost of approximately $200.[15] The Model 1928 followed in 1928, initially produced by retrofitting Model 1921 components, including modifications to the actuator and bolt to reduce the cyclic rate to about 600-700 rounds per minute for improved controllability.[4] This model retained the vertical foregrip but incorporated refinements for military use, leading to its adoption by the U.S. Army in limited quantities that year.[15] Auto-Ordnance handled subsequent production after the Colt contract expired, maintaining small-scale output focused on these configurations until wartime demands escalated. Overall pre-war production totaled fewer than 20,000 units across models, reflecting niche demand and manufacturing challenges.[18]