Thompson sub-machine gun

“Chicago organ grinder”, “trench broom”, “trench sweeper”, “the chopper”, and “the annihilator” were all names given to a ruthless weapon that has been popularized in American culture ever since the first of its kind were invented in 1919 and rolled off the assembly line in 1921. These gruesomely vivid nicknames are sure to make someone realize the sheer might of this weapon and the capability of mass mortality if not used with respect.  The weapon being referred to is the M1921, or better known as the Thompson sub-machine gun. Named after its inventor, John T. Thompson, the gun was invented in 1918 for the purpose of making a weapon that was easily portable, light in weight, and had the capacity of firing rounds at high velocity with a controlled rate of fire. Before the conceptualization of this weapon becoming a reality in warfare, there had never been a gun throughout the entirety of firearms history that had been produced to the specifications like this new weapon concept. It was always thought that with the more fire power and controlled rate of discharge, sacrifices to the guns weight would have to be calculated into the manufacturing of the weapon. However, the manufacturing of this gun re-imagined the possibilities on how weapons can be constructed and frankly transformed the ways in which armies, police officials, and unfortunately criminals conduct their operations of business.

General John T. Thompson holds an M1921 Thompson submachine gun.

(This picture displays retired general and inventor, John T. Thompson, holding his newly invented M1921 sub-machine gun/Senator John Heinz, History Center, In Association with the Smithsonian Institute )

John T. Thompson wanted to change the way in which warfare was fought after seeing the horrors of battle during the first world war. He realized the advantages that a portable, light weight gun would have on the overall aspect of mobilized warfare. He stated that having a lighter more mobile gun would make it easier for soldiers running through battle who needed to get to cover quickly. During WWI, soldiers needed to advance across battlefields through the “no mans zone” to get to new trenches. After seeing soldiers advance through battle, Thompson wanted to create a compact gun that can easily be transported and ran with during a fight. In a journal article written in 1933 by Philip B. Sharpe for the Journal of Criminal Law and Criminology, he states Thompson’s reasoning on why the concept of a light weight gun would be more effective in combat opposed to a gun like the Browning automatic rifle type M1918. “The Browning Automatic Rifle, model 1918, was a moderately successful arm, although its disadvantages were prominent, it was too heavy. The empty gun and magazine weighed fifteen pounds, fifteen ounces. With the loaded clip of twenty rounds of service ammunition, another pound was added.”[1] To compare, the Thompson sub-machine gun only weighed barely 10 pounds. This comparison in weight to the Browning Automatic Rifle is important in understanding the difference in which John T. Thompson wanted in the manufacturing of his weapon. The Browning M1918 was designed to be operated by a team of men, this is what Thompson was aiming to solve with his new machine gun that only took one man to operate. The Thompson gave an advantage to whoever was yielding them because it allowed for much more machine gun units out on the battlefield opposed to standard rifled infantrymen.

Image result for thompson submachine gun parts

(Diagram of all moving parts involved with the manufacturing of the Thompson sub-machine gun/Richard Nicol,Thompson sub-machine gun (side angle), ca. 1930)

The idea that soldiers would be carrying this weapon into battle was crucial in Thompson’s design.  Most importantly in the discussion of the manufacturing of this new weapon, was the fact that a gas operated arm was not practical in the making of the new weapon because it did not fit the ideal design of the gun that Thompson envisioned. “Gas-operation is a system of operation used to provide energy to operate locked breech, auto-loading firearms. In gas operation, a portion of high-pressure gas from the cartridge being fired is used to power a mechanism to dispose of the spent case and insert a new cartridge into the chamber.” This quote from Wikipedia explains the use of gas-operation in firearms which many guns had and still have today excluding the Thompson sub-machine gun. “The principle of locking the action against the explosion is similar to other pressure friction ideas, yet its application in the Thompson gun is radical, essentially different, and stands alone in the automatic field. A wedge-shaped piece of metal weighing one ounce locks the entire mechanism entirely through friction on sliding surfaces created by the breech pressure while the bullet remains in the barrel.”[2] The explanation of the way in which the locking and firing mechanism is implemented in the Thompson sub-machine gun by Philip B. Sharpe greatly shows the way in which John T. Thompson wanted to stray away from the traditional use of gas powered firing mechanisms that would lessen the weight of the gun by getting rid of so many extra parts in substitution with the use of friction as a firing mechanism.

The Thompson sub-machine gun can be appreciated on the battlefield for its light weight portability with the firing power to clear out entire trenches at ridiculous speeds. Being an American made weapon, scholars interested in the origin and history of the Thompson sub-machine gun speculate that it was immediately produced and issued within the United States to military personal and police officers, however, the United States was not at war at this time and in fact the Thompson sub-machine gun saw its first use of military action in the country of Ireland in the hands of members in the Irish Republican Army also known simply as the IRA. The IRA during the years of 1919 to 1921 fought a bloody revolutionary war for the independence of Ireland under British control. The implementation of the Thompson sub-machine gun towards their cause of breaking away from British rule was crucial in the way the IRA fought using guerrilla warfare techniques throughout the country of Ireland. It was crucial for these revolutionaries to have a weapon that was light enough so that when these republican guerrillas attacked members of British military, they could easily make a hasty escape. The implementation of the Thompson sub-machine gun in Ireland was because of an Irish investor who had ties with the Irish Republican Army. This Irish investor’s name was Thomas Fortune Ryan. “Thomas Fortune Ryan was also a senior member of Clan na Gael. The Clan na Gael was an Irish republican organization in the United States in the late 19th and 20th centuries. He was shrewd enough to know a good thing when he saw one. Not only had it [the Thompson sub-machine gun] the prospect of making money, but he also recognized the importance of such a weapon to the hard-pressed IRA at home in Ireland.”[3] In this journal entry written by Liam Farrell, he addresses the intuition that the Irish investor Thomas Fortune Ryan had on the concept of the Thompson sub- machine gun being implemented into the Irish Republican Army and how effective and profitable this weapon could potentially be. Historians can see the influence in which this gun has made internationally in a case of aiding a country in revolution against an oppressor. This sub-machine gun was within the American army in the years containing the events that unfold during World War Two. Areas that would see the use of this weapon range across Europe in fighting the Axis Powers near Germany against Hitler, and on the other side of the globe, throughout the pacific island chains all around mainland Japan. This weapon was an effective and ruthless killing machine however it extended its influence and power from the battle fields and onto the American streets.

Image result for Daniel Field, Georgia Air service command

(This picture displays United States paratroopers learning how to operate and fire the Thompson sub-machine gun from a sitting position/ Daniel Field, Georgia. Air Service Command. Learning to fire a Thompson submachine gun from a sitting position)

Unfortunately, this weapon had also gained a lot of negative publicity due to the use of criminals misusing the gun for their organized crime. They adopted this weapon because it was lightweight, concealable, and did lots of damage in large quantities. In media and popular culture, the Thompson sub-machine gun is stigmatized in association with the classic American gangsters of the 1920’s through the 1950’s. Famous and dangerous criminals like Al Capone, Pretty Boy Floyd, Machine Gun Kelly, Bonnie and Clyde and Legs Diamond to say the least, are all examples of criminals who used the Thompson sub-machine gun in their crimes. In fact, the Thompson sub-machine gun was used in the Valentine’s day massacre on February 14th, 1929, by American gangster Al Capone. This is just one instance of the destructive power of the Thompson sub-machine gun that left seven men dead inside a parking garage on Chicago’s North side. “On February 27, 1926, the story of a shooting incident involving a Thompson sub-machine gun appeared on the cover page of the Chicago Tribune. That day, Al Capone went to a local hardware store and ordered three of these weapons. Capone used the Tommy gun on April 27th of that year in an attack against a rival bootlegger, James Dorothy. These events launched an arms wars of sorts among gangsters in Chicago that quickly spread to other cities.”[4] The effectiveness of the Tommy gun proves the influential effect that this gun had on the American public, specifically the population of citizens involved with organized crime. This influence that spread to other cities across the United States among different criminals across the country proves the effectiveness of the gun and how it was very easy to conceal and how the portability of the gun made it significantly easier to escape the scene of a crime in a faster way.

What is interesting about the history of the Thompson sub-machine gun was that it was first not issued to police officers in cities and counties throughout the country because the rapid fire of the gun was to uncontrollable and could potentially injure or kill an innocent bystander who is involved in a crime scene situation. The unbelievable aspect about the issuing of the Thompson sub-machine gun not to police personal was that the gun did not break any violation with the city of Chicago’s concealed carry laws. In other words, the citizens of Chicago at the time were free to purchase the Thompson sub-machine gun with or without the 50 round magazine drums with no problems, but the people who were responsible for protection of the citizens were not issued the same gun because it was classified as being “too dangerous”.  This fact is astonishing to me as a historian because it makes the history scholar think of the ignorance of the state and city to not allow their own policing officials to carry such an effective weapon, but have no problem with any citizen being able to acquire these types of guns without any of the precautions which comes with gun ownership in today’s day in age. The government let anyone who could afford these weapons the opportunity to purchase them. The guns averaged for about $225 dollars back in 1928 which in today’s age calculates to an estimated $3,283 in 2018. The accessibility of this weapon was quite convenient to people who could afford them, which made the presence of the weapon so dangerous. These weapons had an effect on gun laws, which took away privileges for individuals to obtain weapons and put the weapons in the hands of authority personal like police officers and government soldiers.

The Thompson sub-machine gun can be proven influential not only in the country in which produced and theorized the invention but also in areas all over the world in times of conflict and opposition. This statement is proven with the historical analysis of the Irish Republican Army and their accounts of the use of the Thompson sub-machine gun in the text above. The Irish Republican Party was influential in seeing the potential of the newly invented weapon and showed all of its potential fighting the forces of the British, the government power that had been oppressing and controlling over the country of Ireland at the time in the early 1920’s. The influence of the gun in warfare is also exemplified in the colossal war of World War 2 where many American and other allied forces used the power of the sub-machine gun to fight the enemies of the Axis power consisting of Germany, Italy, and Japan. In relation to the influence the gun had in American popular culture is the most impressive aspect of the gun in opinion. The Thompson sub-machine gun has been associated with the typical American gangster ever since the invention and implementation of the gun onto American society. This machine gun is probably one of the most recognizable symbols that comes to someone’s mind when they speculate the appearance of the typical American mobster because that is what has been engraved in the American perspective by television and movies. This gun is very important in American history not only because of its popularity in American criminal culture but because of its incredible tactical advantages in which it had possessed over the other types of machine guns being produced at the time of its invention.


[1] Sharpe, Philip B. “The Thompson Sub-Machine Gun.” Journal of Criminal Law and Criminology (1931-1951) 23, no. 6 (1933): 1098-114. doi:10.2307/1136114. p. 1101

[2] Sharpe, Philip B. “The Thompson Sub-Machine Gun.” Journal of Criminal Law and Criminology (1931-1951) 23, no. 6 (1933): 1098-114. doi:10.2307/1136114. p. 1103

[3] Farrell, Liam. “The Tommy Gun: The Irish Connection.” History Ireland 8, no.4(2000) 5-6. : p.1

[4] Weaver, Greg S. “Firearm Deaths, Gun Availability, and Legal Regulatory Changes: Suggestions from the Data.” The Journal of Criminal Law and Criminology (1973-) 92, no. 3/4 (2002): 823-42. doi:10.2307/1144246. p. 823

Wikipedia, “The Irish Republican Army” The free online encyclopedia. (2/17/19),

Wikipedia, “The Thompson sub-machine gun” The free online encyclopedia. (2/17/19),

Image Bibliography:

Picture #1:

Daniel Field, Georgia. Air Service Command. Learning to fire a Thompson submachine gun from a sitting position

Digital ID: (digital file from intermediary roll film) fsa 8d40169

Reproduction Number: LC-USW3-034899-D (b&w film neg.)

Repository: Library of Congress Prints and Photographs Division Washington, D.C. 20540 USA

Picture #2:

Title- Thompson sub-machine gun (side angle), ca. 1930

Photographer- Richard Nicol

Date- ca. 1930

Location- United States–Washington (State)–King County–Seattle;

Digital Collection- King County Museum Collections

Repository- Seattle Metropolitan Police Museum-

Picture #3:

Picture of Thompson holding his newly invented weapon

Date- ca. 1921

Digital Collection- Senator John Heinz, History Center, In Association with the Smithsonian Institute


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