The Thompson, popularly nicknamed the "Tommy Gun", is an American submachine gun that was designed by John Talliaferro Thompson and produced by the Auto-Ordnance Corporation. Originally conceived during World War I as a portable machine gun to break the stalemate of trench warfare, the Thompson entered production in 1921 and was primarily marketed for law enforcement purposes.

The Thompson's extensive use by gangsters during the Prohibition era, and by Allied troops during World War II, cemented the gun's image into popular culture, and consequently it has become of the most recognizable guns in history.[1]


The Thompson Submachine Gun was designed by John T. Thompson who was inspired by the trench warfare of World War I to develop a "one-man, hand-held machine gun", firing a rifle caliber round. While searching for a way to allow such a weapon to operate safely, Thompson found a patent issued to John Bell Blish.
A Thompson-and-his-gun

John T Thompson holds the 1921 Thompson submachine gun

Thompson found a financial backer, Thomas Fortune Ryan, and founded the Auto-Ordnance Corporation in 1916 to develop his weapon. The main designers of the weapon were Theodore Eickhoff, Oscar Payne and George Goll.

By the end of 1917, shortcomings of the Blish lock were found, and it had been discovered that the only cartridge currently in U.S. service suitable for use with said lock was the .45 ACP. The project was then titled Annihilator I, and by 1918, most of the design issues had been resolved.

On 11 November 1918, the Annihilator prototypes were put into crates, sent to the docks in New York and were attempted to be sent to Allied troops in Europe; however, the war ended the same day just a few hours later and as such were never actually sent to Europe. As a result of this, the Annihilators remained in said crates and the docks for weeks on end until they were brought back to the factory.

Officially renamed the Thompson submachine gun in 1919 at an Auto-Ordnance board meeting, the Thompson was the first weapon to be marketed as a submachine gun despite there having been weapons being made with a similar purpose in the recent past.

The Thompson entered production in 1921 and was marketed to both militaries, civilians and similar agencies, though its high price resulted in few sales. A Thompson cost around $200 each, with one twenty-round magazine costing $20; this was in comparison to the .45 ACP M1911 pistol which cost only $17.45, and the time of the depression meant that the Thompson didn't sell very quickly.

M1921 Thompsons were first sold in small quantities to the U.S. Post Office in an attempt to protect the mail from a spate of robberies, followed by adoption by several police departments in the United States and minor international sales to various armies and constabulary forces located mainly in Central and South America. Some Thompsons were also acquired by the Irish Republican Army from supporters in the U.S. despite their high price, and were known to have been used during the Irish War of Independence and the Irish Civil War.

The Thompson achieved most of its fame and notoriety in the hands of Prohibition and Depression-era gangsters, as well as its portrayal in in Hollywood films. Nationalist China also acquired a number of Thompsons for use against Japanese land forces; this eventually led them to produce copies (or derivatives) of the Thompson for their own use by its various armies and militias.

Soon, John T. Thompson decided to sell his gun to the public, stating it was the just the gun for home defense. The Thompsons could be bought at hardware stores and even through the mail. Production, however, remained slow until the onset of World War II, at which point Thompsons were being produced in significantly larger quantities. In 1939, the Thompson was the only submachine gun in production outside of Europe, and as a result the British, French and Swedish governments hurriedly placed orders for these guns.

The Thompson was adopted by the US Army in 1938, serving during World War II and later into the Korean War, as well as early stages of the Vietnam War. Other Allied countries purchased the Thompson as well, notably the United Kingdom and France; however, the French never got the chance to use them to their full potential as France lost to Germany in just a few weeks. Modifications to simplify production and reduce cost were made in 1942, resulting in the M1 and M1A1 models, commonly carried by both non-commissioned and commissioned officers.

Thompson had intended his weapon to be used as a trench-clearing weapon to quickly sweep trenches and clear out enemies; this concept was later adopted by the Germans where this technique was used in tandem with Sturmtruppen (lit. stormtrooper) techniques.

The Thompson found particular utility during World War II in Allied hands as a weapon for use by patrol leaders, non-commissioned officers, scouts and similar units. The Thompson was a common sight in the European Theater, being used by British and Canadian commando units and American ranger battalions and paratroopers; the paratroopers liked the Thompson and used it to great effect by "borrowing" these Thompsons from members of mortar squads for use on patrols and similar missions.[2]

In the Pacific Theater, most Commonwealth forces like the Australian Army initially used the Thompson extensively in jungle patrols and ambushes; however, due to its weight, the weapon was eventually replaced by similar weapons like the Owen gun and Austen The U.S. Marines also used the Thompson in limited numbers, where it was a common sight during their later island assaults.

The Thompson was soon found to be ineffective in heavy jungle cover, as the low-velocity .45 bullet was found to not be able to penetrate most small-diameter trees, Japanese helmets or protective vets (in 1923, the Army had rejected the .45 Remington-Thompson, which had twice the energy of the .45ACP). Thompsons were also a common sight in the early phases of the New Guinea and Guadalcanal campaigns where they were used for jungle patrols by American forces, but they ended up being replaced by the Browning Automatic Rifle to fulfil the same purpose.

The Thompson was rendered thoroughly obsolete by the beginning of World War II as many European nations had developed cheaper, simpler and equally effective weapons; however, they remained in use and were used to great effect. By the time of the Korean War, the Thompson had been retracted from service as a standard-issue submachine gun with American forces and was replaced by the M3 submachine gun and the M1 carbine in that role.

The M3 submachine gun's supposed role was to apparently have it slowly drafted into service and to have it produced in large enough a number to replace the Thompson and have the latter retracted from frontline service; this never happened though as the Thompson was never really replaced by the M3 due to constant requests for modifications and unforeseen production delays of the M3. Due to this, the number of Thompsons in active service amounted to three times the amount of M3s in service by the end of World War II.

Many Thompsons were later distributed to Chinese armed forces as a form of military aid before Chiang Kai-shek's government fell to Mao Zedong's communist regime in 1949. Many American troops were surprised to see the amount of Thompsons in use by these Chinese communist forces during the Korean War, especially during nighttime ambushes. Many of these weapons were later recaptured and placed back into service with American soldiers and Marines for the rest of the war.

The Thompson also saw limited service with the U.S. Marine Corps (carrying over from their Post Office service) as the M1928 in a series of interventions in Central America (particularly Nicaragua), where it was used to counter ambushes by guerrilla forces. Some forces were also armed with Thompsons during the Vietnam War, but the weapons were quickly replaced by the M16.

The Thompson was also used by U.S. and overseas law enforcement and police forces, with their most prominent user being the Federal Bureau of Investigation (or FBI). The FBI first acquired Thompsons in 1933 in response to the 1933 Kansas City Massacre and used them until 1976, at which point they were declared wholly obsolete. As a result, any and all Thompsons in U.S. government possession were destroyed, save a number of token museum pieces and training models.[3]

The Thompson, or copies of the gun, are still seen from time to time in modern day conflicts, such as the Bosnian War.

Design details

The Thompson, especially the early Model 1921, has a fairly high rate of fire at 900+ rounds per minute (rpm), higher than many other submachine guns of smaller caliber. This rate of fire, combined with a stock with excessive drop, increases the tendency of the weapon to climb off target in automatic fire; however, proper shooting techniques can alleviate this somewhat. Compared to modern 9mm submachine guns, the .45 Thompson is quite heavy. By the standards of the day, the Thompson was one of the most effective and reliable submachine guns available.

Due to its association with gangsters and World War II, Thompsons are highly sought as collector's items, with an original M1928 in working condition easily fetching US$20,000 or more. Semi-automatic versions are currently produced by the Auto-Ordnance Company, a division of Kahr Firearms (no relation to the original Auto-Ordnance Company). A total of approximately 1,700,000 of these weapons were produced by a number of companies (Auto-Ordnance, Savage and Colt just to name a few), of which 1,387,134 were M1 and M1A1s.



Main article: Thompson Persuader

The precursor of sorts to the Thompson that was never completely finished. It was said to have never worked as intended, with one prototype known to survive today.

The weapon feeds from what is described as a "tape" belt and never fired more than six or seven shots consecutively due to the stress exerted on the Blish lock knocking it out of place.

The second prototype of the Persuder. While it resembled the later M1919 greatly, the weapon was still in essence a belt fed submachine gun as it fed from the same belt system as the Persuader did. It is unknown if the Persuader II was ever built, as the only known image of it is a sketch.


The "original name" of the Thompson,[4] the Annihilator was essentially the immediate precursor to the M1919 prototypes. The Annihilator fed from a twenty-round detachable box magazine and has a distinctive barrel shroud likely identical to that as on the Persuader. The weapon's magazine arrangement is stated to be an interim design.


The first "proper" Thompson, the M1919 took the appearance of later Thompson submachine guns with twin grips and a top-mounted charging handle. Multiple variants of the M1919 were made, all being slightly different in appearance.[5]


Thompson M1921
The M1921 was the first production variant of the Thompson and also the first produced in volume, with an estimated 15,000 made. Infamous for use during the Prohibition era, the Thompson in this variant became well known for its use during street crime during the roaring twenties.

The weapon was select-fire with a detachable buttstock with a rate of fire of 800 RPM. The weapons used Lyman sights, Remington stocks and grips and Colt firing mechanisms. Cutts compensators were added as an option later, with weapons with the Cutts compensator being sold at the weapon's original price of $200.[6]

A light support weapon version of the Thompson, the M1923 was sort of a failed experiment as an attempt to expand Auto-Ordnance's product line; the weapon was marketed primarily towards the European Market but failed to get any buyers.

The first variant of the Thompson to be officially used in any capacity by any sort of armed forces. Essentially an M1921 with a bolt weight added to lower the weapon's rate of fire, the M1928 was eventually colloquially named the "overstamp" as an "8" was stamped over the last "1" in "M1921" as a fairly crude model name update.

Thompson 1928A1
An update over the M1928, the M1928A1 was said to be a transitional model which was essentially a militarized version of the M1928, the latter being meant for use by the navy. Notable differences between both weapons include a different forearm and provisions for slings. A total of 562,511 were produced; despite the high production numbers, as with most other variants of the Thompson, the M1928A1 was still rather expensive.

An experimental variant with a strangely-shaped inline stock and elevated sights also exists.[7]

Service variants

A simplification of the design produced on request of the US Army, the design, officially known as the United States Submachine Gun, Cal. .45, M1, was heavily simplified from the M1928, with a simpler L-shaped rear sight and the ability to take drum magazines removed from the M1 due to a new magazine catch. The M1 was also notably much cheaper than the M1928 and other Thompson variants as the oiling system and Blish lock were removed. A total of 285,480 were produced.

A further simplification of the M1 design, the M1A1, officially designated the United States Submachine Gun, Cal. .45, M1A1, changed minor elements of the gun such as the bolt in an attempt to further lower production costs; despite the price difference between the M1 and M1A1 being rather negligible, the M1A1 was still notably far cheaper than its predecessors. A total of 539,143 were produced.


A semi-automatic version of the M1921, the M1927 was essentially a M1921 modified internally with certain parts replaced. Despite being a semi-automatic weapon, the weapon is said to be rather easy to convert back to being fully automatic, with most police-owned M1927s having been converted back to full-auto.

Due to the National Firearms Act of 1934 and a 1982 BATF ruling, the M1927 is classified as a machine gun by law as it is "readily convertible to full-auto by swapping parts" due to the former and because it is a semi-automatic open bolt firearm due to the latter (all semi-automatic open bolt firearms produced after the date of ruling are classified as machine guns under this law).

A modern semi-automatic replica of the Thompson produced by the Kahr-owned Auto-Ordnance Corporation (no relation to the original company) based in West Hurley, New York. The M1927A1 is sold as a rifle by Kahr.

Produced since the 1970s, the M1927A1, A3 and A5 are chambered in .45 ACP, .22 Long Rifle and .45 ACP respectively, although the A5 is essentially an A1 sans stock. It appears that only the M1927A1 remains in production, with the M1927A3 and M1927A5 possibly having been discontinued in the late 1980s or early 1990s.


Main article: Thompson M1926

A licensed version of the Thompson design produced by Birmingham Small Arms of the United Kingdom. Featuring a different design than its American contemporary, the M1926 as it was called was chambered in 9×19mm Parabellum and tested by the French and Belgian militaries but was ultimately never adopted; only a few were produced.


A Thompson produced in Egypt that is said to be one-of-a-kind.[8] The weapon has an original Thompson barrel from Auto-Ordnance but everything else appears to have been made in Egypt; the weapon is noted to be of poor quality. Rather interestingly, the weapon sports a cylindrical receiver.[9]

The weapon is said to currently be located in the National Firearms Center in the United Kingdom, hidden from public view.[8]


  • The Thompson submachine gun, more specifically the M1928 and M1928A1 variants, are the last weapons used by the US Army with a year designation in the weapon's official nomenclature.


  • Helmer, William J., The Gun That Made The Twenties Roar, 1969