You’ve seen it in every black-and-white gangster flick ever made. A guy in a trench coat and a fedora pulls a heavy, wooden-stocked weapon out of a violin case and lets fly a hail of bullets. It’s the "Chicago Typewriter." The "Chopper." The "Annihilator." But if you’re asking when was the Thompson submachine gun invented, the answer isn't a single afternoon in a workshop. It was a messy, desperate race against the clock during the bloodiest war the world had ever seen.
John Taliaferro Thompson didn't just wake up one day and decide to arm the mob. Honestly, he was a retired Army officer with a obsession. He wanted a "trench broom." He saw the stalemate of World War I—men dying by the thousands in the mud of No Man's Land—and realized the bolt-action rifles of the era were garbage for close-quarters fighting. By the time the first functional prototypes emerged in 1918, the war was basically over.
Timing is everything.
The 1916 Breakthrough and the Blish Lock
The soul of the Thompson wasn't actually invented by Thompson. It was a Commander John Blish. In 1915, Blish noticed something weird while working with large-caliber naval guns. He saw that under extreme pressure, different metals tended to stick together. He called it the Blish Principle.
Thompson, being a savvy guy, snatched up the patent. He formed the Auto-Ordnance Corporation in 1916. He didn't have a factory. He didn't have a finished design. What he had was a theory and a small team of engineers—guys like Theodore Eickhoff and Oscar Payne. They spent the next two years trying to turn a naval physics observation into a hand-held weapon that wouldn't blow up in the shooter's face.
It was a nightmare.
Early designs were recoil-operated, but they were fussy. They tried using rifle rounds, but the pressure was too high for the Blish Lock to handle. Eventually, they settled on the .45 ACP—the same round used in the 1911 pistol. This was the turning point. The heavy, slow-moving bullet was perfect for a short-range, high-volume-of-fire weapon. By 1917, the "Persuader" was born. It was belt-fed and looked like something out of a steampunk novel.
The "Annihilator" and the Armistice
By the summer of 1918, the design was finally coming together. They renamed it the "Annihilator." It ditched the belt feed for a more practical magazine. Thompson finally had his trench broom. He rushed the first shipment to the docks in New York, ready to send them to the front lines in France.
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Then the world stopped.
The Armistice was signed on November 11, 1918. The war was over. The massive military contracts Thompson was counting on vanished overnight. The gun was "invented," sure, but it was a weapon without a war. This is why the Thompson didn't actually hit the commercial market until 1921.
Why the 1921 Model Changed Everything
When people talk about the "Tommy Gun," they are almost always picturing the Model 1921. This was the first production version. It was beautiful. It was expensive. It was heavy.
A single Thompson in 1921 cost about $200. To put that in perspective, a brand-new Ford Model T cost about $400. You were essentially carrying half a car in your hands. Because it was so pricey, the U.S. military—which was broke after the war—ignored it. The police departments thought it was too much firepower.
So, who bought it?
Ranchers. Coastal guards. And, unfortunately for Thompson’s reputation, the criminal underworld. The gun was incredibly well-made. The cooling fins on the barrel, the fine walnut furniture, the intricate machining—it was a luxury item that happened to spit 800 rounds per minute.
Design Flaws and the "Blish" Controversy
Here is something most "gun guys" won't tell you: the Blish Lock was kinda pointless.
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Modern ballistics experts have tested the original 1921 and 1928 models and found that the "adhesion" principle Blish swore by didn't really do much for a .45 ACP cartridge. The gun worked because it was heavy and the bolt was massive, not because of some magical metal friction. Eventually, during World War II, the military realized this. They simplified the design into the M1 and M1A1, removing the Blish Lock entirely and turning the gun into a simple blowback weapon.
It worked better. It was cheaper. It was faster to build.
The "sophisticated" invention of 1918 was actually over-engineered. But that over-engineering is what gave the early Thompsons their iconic look—the top-mounted charging handle and those beautiful cooling fins that looked like a radiator.
The Thompson in the Streets vs. The Thompson in the Trenches
By the mid-1920s, the invention had taken on a life of its own. It’s a common misconception that the Thompson was "the gun that won the war" twice. In reality, it was "the gun that defined the 20s" and then got drafted for the 40s.
The Gangster Era (1924-1934)
The Tommy Gun became the superstar of the Prohibition era. Names like Al Capone and John Dillinger made it a household name. The St. Valentine's Day Massacre in 1929 was the final straw for the American public. Two Thompsons were used to pump 70 rounds into seven men in a Chicago garage.
This led directly to the National Firearms Act of 1934. The government didn't ban the gun, but they taxed it out of existence for the average person. A $200 tax on a $200 gun? In the middle of the Great Depression? Forget it.
The Military Comeback
It took the threat of Nazi Germany to make the Thompson a "good guy" gun again. In 1939, the British were desperate. They started buying every Thompson they could get their hands on. By the time the U.S. entered the war, the Auto-Ordnance Corporation couldn't build them fast enough.
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But there was a problem. The 1921/1928 design was too slow to manufacture. It required hours of skilled lathe work.
The military demanded a redesign.
The M1 version, which appeared in 1942, stripped away the luxury. No more drum magazines—they rattled too much and jammed anyway. No more vertical foregrip. No more Blish Lock. This "invented" version of the Thompson was a rugged, simplified beast that served from the sands of North Africa to the jungles of Guadalcanal.
Breaking Down the Timeline
If you need a quick reference for the evolution of this weapon, here is the messy reality of its development:
- 1915: John Blish patents the "Blish Lock" based on naval gun physics.
- 1916: General John T. Thompson founds Auto-Ordnance to build a "trench broom."
- 1917-1918: Prototypes like the "Persuader" and "Annihilator" are developed.
- 1919: The "Model 1919" is showcased, but only about 40 are ever made.
- 1921: The first full production model hits the market. This is the "classic" Tommy Gun.
- 1928: The Navy version arrives, slowing down the rate of fire to make it more controllable.
- 1942: The M1 version is standardized for WWII, marking the death of the original complex design.
Why the Thompson Still Matters
You might wonder why we still care about a heavy, expensive gun from over a century ago. Honestly, it’s about the soul of the machine. The Thompson represents a specific moment in the history of technology where craftsmanship met the industrialization of death.
It wasn't just a gun; it was a cultural shift. It forced the U.S. government to change how it regulated firearms. It changed how police departments armed themselves (leading to the creation of SWAT mentalities later on). And it proved that a portable, high-capacity automatic weapon was the future of infantry combat.
Even today, the Thompson is one of the most recognizable silhouettes in the world. Whether it's in a video game like Call of Duty or a museum display, it carries a weight—literally and figuratively—that modern plastic rifles just don't have.
Summary of Key Takeaways
- It missed its original purpose. It was designed for WWI but finished just as the war ended.
- It was a luxury item. The original 1921 model was prohibitively expensive for most people.
- The "Blish Lock" was a myth. The physics that supposedly made the gun work were largely unnecessary for the caliber it used.
- World War II saved it. The massive contracts from the Allied forces turned a niche gangster tool into a legendary military icon.
- Simplification was key. The best version of the gun (the M1A1) was the one that threw away most of the original "inventions" to prioritize reliability.
If you are looking to research the Thompson further, start by looking into the National Firearms Act of 1934 records or the Auto-Ordnance Corporation archives. Understanding the Thompson requires looking at both the engineering patents of the 1910s and the social chaos of the 1920s. It is a rare piece of tech that is inseparable from the history of the era it inhabited.
For those interested in the mechanical side, look up the difference between the M1928A1 and the M1. The transition from a complex, friction-locked bolt to a simple blowback system is one of the most fascinating "evolutions" in firearm history. It shows exactly how the pressures of war force inventors to stop being "clever" and start being "practical."