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The Thompson Submachine Gun, the Gun That Made the Twenties Roar

A look at America's first submachine gun and its important place in history!

The Thompson Submachine Gun, the Gun That Made the Twenties Roar

America’s first submachine gun was the iconic Thompson, originally developed as a Trench Sweeper for World War I. (Photo courtesy of Ruben Mendiola and

From the streets of Chicago, to the hands of notorious gangsters such as: "Machine Gun" Kelly, "Pretty Boy" Floyd and Public Enemy Number One, the Thompson Submachine Gun found itself on both sides of the law. It would be seen in the hands of the Police, lawfully armed citizens and even Winston Churchill. Nothing swept a trench like it and nothing made the Twenties "roar" like the .45 Caliber Thompson Submachine Gun.

The Thompson Submachine Gun is likely one of the most popular and noted weapons of its type, especially in American history. Outside of its iconic lines and unique appearances from newspaper headlines to battlefields, how much is truly known about the firearm and the inventor of the Thompson? John Taliaferro Thompson, inventor and the man which would lend his name to the firearm was a native of my home state of Kentucky. Born in Newport Kentucky on December 31, 1860 he would grow up here. Being the son of Lieutenant Colonel James “Jim” Thompson would heavily influence his decisions as an adult, thus thrusting him into a military career.

Thompson Submachine Gun
When the United States entered World War I it quickly adopted the French Chauchat automatic rifle which had very a limited magazine capacity (only 16 rounds in .30-’06) and which proved less than reliable in the trenches.

Graduating from West Point Military Academy in 1882, he was stationed to the 2nd Artillery in Newport Kentucky where he would receive training in engineering. In 1890, John Thompson would be assigned to the U.S. Army Ordnance Corps. Thompson began studying the effects and changes upon the modern battlefield and found that antiquated “Napoleonic tactics” were no longer suited, especially with the high degree of accuracy found in repeating bolt-action infantry rifles, quick-firing field artillery and the invention of Maxim’s machine gun. He also found the limitations of infantry rifles such as the US M1917 (based off of the P-14 Enfield) and Springfield 1903 rifles had in close-range trench warfare.

With this, Thompson set out to produce what would effectively be nicknamed the “Trench Sweeper”, a smaller, more maneuverable, yet powerful firearm that offered impressive capacity and great effectiveness at close range. Thompson took great interest in a design from John Bell Blish. The patented “Blish lock” was a break locking, friction-delayed blowback action working from the principle of: “two dissimilar surfaces and materials, placed under extreme pressures would resist the force of friction”, this is now known as static friction.

Thompson Submachine Gun
The Thompson submachine gun was used by both gangsters and the police officers bringing them to justice.

With modern technology, the Blish system is often considered massively outdated, with running theories that it actually failed to function as theorized. Thompson would incorporate the Blish lock system into his Thompson SMG, along with the M1911 service pistol’s .45 Auto cartridge, for ammunition interchangeability. Unfortunately, the Thompson wouldn’t catch on until after World War I.

So, how does the Thompson SMG fair in terms of modern weaponry? Especially considering numerous advances in pistol caliber submachine guns and personal defense weapons since its initial design? The answer is both good and bad. While there is no denying the effectiveness of the .45 Caliber SMG at close range, the weight of both the firearm and loaded magazine make it a very cumbersome weapon for even the most seasoned of users. The Thompson 1928A1 weighs in at an astounding 10.8 pounds empty, rivaling that of many battle rifles and surpassing the weight of Assault Rifles currently fielded by modern militaries. With a 100-round drum magazine, the Thompson Model 1921AC will accrue more weight than that of the M1918A1 Browning Automatic Rifle and Colt R80 "Monitor". That is a considerable amount of weight, especially considering the translation of that weight into effective range and the use of a pistol caliber.

Thompson Submachine Gun
The Model 1921 Thompson was a handsomely machined firearm which proved to be quite reliable and very effective. (Photo courtesy of Ruben Mendiola and

With the weight, the practical ineffectiveness of John Blish's "Blish system" and the cumbersome nature of the Thompson Submachine Gun, it is understandable how the Thompson was lost in the translation of time and technological advances. When comparing it to more modern offerings such as the Heckler and Koch UMP in .45 Auto, the differences are evident and numerous. The Thompson weighs in over double that of the UMP's 5.2 pounds, with a higher cyclic rate of 700-800 rounds per minute. It is also noted that the Thompson is far from modular, like modern offerings, with a long and uncomfortable buttstock that’s extremely cumbersome when shouldering. I found that when working with a 1921/28 Colt Overstamp Thompson, it felt more natural to lock the stock under my armpit and ultimately "point" the firearm, instead of shouldering it and using the sights. This is unfortunate, because the 1921/28 Thompson utilizes very nice sights and gives a nice sight picture. I find the sights on the 21/28 Colt almost too complex for a .45 Caliber submachine gun however. The Thompson M1’s more simplistic sight picture is much more applicable to that of a close-quarters combat weapon.

Thompson Submachine Gun
The downside to the M1921 Thompson was how expensive it was, long manufacturing time, overall weight, long length of pull and high rate of fire. (Photo courtesy of Ruben Mendiola and

The Thompson is complex, large, cumbersome, heavy and non-modular. Does that make the Thompson a "bad firearm"? Absolutely not, the Thompson is a good firearm and served not only our military, but foreign militaries well for years. It is better to say that the Thompson is simply dated in comparison to modern offerings, but was an absolute showstopper and technological marvel of its time.

Thompson Submachine Gun
A look at the markings and controls of a Model 1921 Thompson. (Photo courtesy of Ruben Mendiola and

Many people, including myself will view the "negatives" of the Thompson while ultimately forgetting the design is now over 100 years old. It comes from a time where modern arms and offerings simply didn't exist and the modern combat rifle (Assault Rifle) wasn't even a dream of Hugo Schmeisser's. The majority of soldiers were issued bolt-action rifles with designs ultimately reaching back into the late 19th century. The large amount of automatic weapons on the battlefield at this time were crew served, or large automatic rifles such as the French Chauchat or Browning Automatic Rifle, both of which fired full-fledged rifle cartridges, with limited magazine capacity and weighed in at 16 to 20 pounds. While Germany did have submachine gun offerings, such as the Bergmann MP-18 for example, the United States was largely lacking in the submachine gun department. While the Pedersen device (chambered in 30-18 Auto/7.65x20mmFL) did exist for the 1903 rifle, it never saw combat.

Thompson Submachine Gun
The Cutts compensator was intended to reduce muzzle rise and aid control on full automatic. (Photo courtesy of Ruben Mendiola and

While the Thompson was replaced shortly after the Korean War, with limited use in Vietnam, it is a crucial and important firearm in not only American military history, but also firearms history as well. It is a pivotal design and ultimately helped pave the way to other firearms. While not perfect, the Thompson is a marvel for its time, giving unrivaled capacity to caliber ratio and a solid foothold for the United States into the submachine gun world. While initially having a slow start in terms of sales, and a staggering price of $200 (or roughly half the price of a Ford Model T), the Thompson is more than just iconic lines. It is one of the most important American military arms of the 20th century.

Today the Thompson is a highly desirable collector’s item and a wonderful shooter. The value of registered examples has skyrocketed in recent years. They are prized for their place in history, their craftsmanship, and their ability on the range. If you are interested in owning your own Thompson submachine gun the place to start your quest is Ruben Mendiola and A highly respected machine gun dealer, they are very well-acquainted with all manner of collectible and shooter grade Thompsons.

If you have any thoughts or comments on this article, we’d love to hear them. Email us at


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