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M1 Thompson (Tommy Gun)

Submachine Gun (SMG)

United States | 1938

"The famous M1 Thompson Submachine Gun of World War 2 fame was a fantastic piece of firearms engineering for its time."

Authored By: Dan Alex | Last Edited: 05/30/2019 | Content ©www.MilitaryFactory.com | The following text is exclusive to this site; No A.I. was used in the generation of this content.
The Thompson series of submachine guns (not quite a pistol yet not a full-fledged machine gun) began life in 1919 following World War 1. It was the creation of one General John Taliaferro Thompson (December 31st, 1860 - June 21st, 1940) who started work on early forms as early as 1917. Since then, the weapon system went on to make its mark in the Prohibition era (fighting for both gangsters and police forces alike), found tremendous combat successes in World War 2 and saw use in the Arab-Israeli War of 1948, the Korean War, the 1st Indochina War, the Vietnam War, the Chinese Civil War and the Bosnian War to name a few conflicts. Some 1.7 million copies of this fine weapon have been produced with production beginning in 1921 and continuing to this day.


General Thompson, son to an Army Lieutenant Colonel, took to heart the hard lessons being learned in "trench warfare" tactics of World War 1. The infantryman was generally issued a long bolt-action rifle (that is, every round had to be manually prepped into the chamber before firing through use of a bolt lever) with attached bayonet. While the rifle proved worthy of ranged warfare, it was of little value in the confined spaces of the trench networks dotting the European countrysides. When in close quarters, the bayonet, attached along the underside these long rifles, was hardly the answer to the common soldier and a better solution was in order. Additionally, World War 1 was a sort of battlefield where the appearance of even a single machine gun - and its inherent firepower, not to mention the psychological implications - could very well make-or-break a given offensive.

As such, Thompson - with an education in engineering and artillery and work experience in the US Army's Ordnance Department - envisioned a "hand-held" version of a machine gun - a portable "trench-sweeping" system capable of operation by a single soldier and optimized for use in intimate quarters. The challenge lay in devising a system that was relatively simple, safe to use and made to fit into the hands of the standard infantryman.

In 1915, John Bell Blish received his patent for a friction delayed blowback firing action to which Thompson happened across. The method of fire basically called for the slowing down of the breech by frictional forces accomplished by two obliquely-angled blocks sliding over one another. This operation could effectively bring down the cyclic rate-of-fire of a given weapon system and seem to be what Thompson had been searching for. Thomas Fortune Ryan provided the funding and Thompson began his Auto-Ordnance Corporation in 1916. Design followed under the name of "Annihilator I" and the American military .45 ACP round was selected - this essentially being the only cartridge round suitable for use in the type of Blish firing action being used.

The design was completed in 1918 but missed out on potential orders with the close of World War 1. Had it been produced and delivered in time, it is interesting to envision the Allied soldier perusing the deadly trenches of Europe with his Thompson in hand. In post-war America, the Annihilator name was now dropped in favor of "Thompson Submachine Gun". Most further development would now occur in the commercial market with the military showing little interest in such a system.

The German MP18

It should be noted that the first practical submachine gun was actually of German origin and fielded in World War 1 as the MP18 ("Machine Pistol" and noted by the initial year of service being 1918). It was a development of Hugo Schmeisser in 1916 and produced by Theodor Bergmann under Bergmann Waffenfabrik, serving the German Army and others from 1918 through 1945. It operated from an open bolt/blowback principle and made use of 9x19mm Parabellum with a rate-of-fire equal to 500 rounds-per-minute. The implication of this weapon in the war forced the Versailles treaty to restrict future development of the weapon type - though the foundation of the "submachine gun" class had already been laid only to be perfected by the time of World War 2. In essence, this shows how many other forces in the world were also in the same line of thinking at the time - to devise a capable portable system fielding the firepower of a machine gun.

M1921 - the First Thompson

The M1921 became the first Thompson model to be produced and this only found a few homes in the civilian, government and police markets, many put off by the types high costs. Despite some security and military use, the Thompson soon found popularity amongst the gangsters of the Prohibition era and, equally, in the police forces charged with taking them down.

Second World War

With rumblings of World War again in the air, overseas operators such as China purchased and operated the weapon against Japanese forces. The US military officially took on the weapon in 1938. While the M1928A1 was the weapon on hand by the time of the Japanese attack on Pearl Harbor, a simplified version was desperately needed to fill the needs of the US military. As such, the simplified M1 and M1A1 soon appeared.

Combat actions led the weapon to be used in both European and Pacific battlegrounds - proving more effective in the former. European allies were surprised to see Germans making large-scale use of submachine guns themselves and quickly clamored for a similar weapon with help from the United States. Orders began coming in and, while Yugoslavian and French orders were diverted with their respective falls, the United Kingdom became one of the principle early operators of the Thompson.

Patrols in the Pacific soon made use of the more powerful BAR light machine gun it place of their Thompsons. The high rate-of-fire offered by the little machine gun and man-stopping qualities inherent in the .45 ACP slug proved a godsend to troops in close-quarters though this was offset to an extent by the weapons heavy weight and unique ammunition. Despite its issuing to Soviet troops via Lend-Lease, the lack of available .45 ammunition in the country led to its limited use along the East Front. The weapon saw use in the hands of American, British, Australian and Canadian forces. By late 1944, the M3 "Grease Gun" series - a much cheaper production alternative - was replacing the Thompson in service - though many still appreciated the qualities of the their Thompsons instead.

The Thompson appeared in the Korean War and, perhaps more amazingly, in the Vietnam War. It was also reported to be in use during the Bosnian War (1992 - 1995).

Thompson Details

The Thompson maintained a unique profile never seen before and never repeated again. The body bore a boxy type appearance with the rear sight dominating the top rear end. The pistol group was mounted midway under the body with the "stick" type magazine just forward of that. The barrel (of the M1) was fitted with a forward sight at the barrel end and the underside held a horizontal foregrip of wood. Wood also complimented the pistol grip and the fixed buttstock. A sling could make use of the lugs located at the buttstock base and the foregrip base. The ammunition ejection port was to the right side on top of the weapon just above the magazine feed. The rear sight of a flip-up adjustable sight.

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The Variants

The "Persuader" and "Annihilator" were both experimental approaches of the Thompson submachine gun design idea. The Persuader was essentially a belt-fed version appearing in 1918 while the Annihilator was a box-fed model fitting the 20- and 30-round box magazines appearing in 1918 and 1919.

Model 1919 saw limited production examples totaling just 40 units. The Model 1919 did not feature a buttstock or front sights and was fully-automatic, utilizing Colt .45 ammunition (though other ammunition types were tested). Its rate-of-fire was listed at an amazing 1,500 rounds-per-minute and was demonstrated to the US Military in 1920 though only some New York City Police sales amounted.

Model 1921 became the first quantitative production model of any Thompson submachine gun totaling some 15,000 examples in all. Rate-of-fire was listed at 800 rounds-per-minute and became a favorite of Prohibition-era gangsters and police forces alike.

Model 1923 was an attempt by Auto-Ordnance to showcase the weapon to the US Army. This model operated with the .45 Remington-Thompson cartridge allowing for more range and better penetration at distance. The Model 1923 also brought along new changes to the Thompson submachine gun family line in that it introduced a bipod, bayonet lug, sling and horizontal forearm. However, by this time, the Browning Automatic Rifle (BAR) was already adopted by the US Army and the Model 1923 would be essentially filling the same role in service. As such, now further thought to adopting the Model 1923 was given.

Model 1927 was based on the M1921 but fitted with an open bolt assembly and offering a semi-automatic fire mode only (conversion to full-automatic mode was simple enough however). The Model M1927A1 (also "Thompson Semi-Automatic Carbine") was a semi-automatic version produced for the civilian market between 1974 and 1999. Production was handled by Kahr Arms of Massachusetts. Auto-Ordnance of West Hurley produced the Model 1927A3, another semi-automatic form but firing a .22 caliber cartridge. The Model 1927A5 became a semi-automatic .45ACP pistol version also produced by Auto-Ordnance. Production is still ongoing.

Model 1928 was the first Thompson submachine gun to achieve widespread use by US military forces consisting of the US Marine Corps and US Navy. The Navy requested that the cyclic rate-of-fire be brought down so Model 1928s were essentially Model 1921s with added weight in the actuator. With the arrival of World War 2 in Europe, the Model 1928 began to see large production orders.

The M1928A1 Thompson (or more specifically as "Submachine Gun, Cal. .45, M1928A1, Thompson") appearing in 1928 operated from a delayed blowback system. These weapons were issued to reconnaissance and armor group elements and featured selective fire settings for semi- or full-automatic modes along with a removable buttstock. Fire selection was via a switch along the left side of the body while the buttstock was removable via two screws along the underside - though the buttstock was generally left on to help in stabilizing aim. Additionally, some were produced without the horizontal foregrip and made with a vertical one instead. The charging handle was fitted to the top of the receiver and cooling fins were apparent along the barrel. The gun was fed via a 20- or 30-round detachable box magazine or a 50-round drum and utilized .45 caliber ammunition. Magazine counts also included a little-known 18-round magazine and a 100-round drum. The rate-of-fire was between 600 and 725 rounds-per-minute. A Cutt's muzzle compensator was added in an attempt to divert gasses upwards and keep the barrel down when firing. This proved of limited value and added more complexity to the build, being left off of later M1928A1 production examples. The M1928A1 maintained a length of 33.75 inches and an unloaded weight of 10lbs, 12oz. The barrel measured at 10.50 inches and sported a 6-groove, right hand twist.

For all intents and purposes, however, the M1928A1 proved much too heavy for the standard infantryman to lug around all day and too expensive to produce in wartime. The 50-drum magazine - while sound in theory - proved to add much unneeded extra weight and made for too much noise when silence was imperative. The M1928A1 was based highly on the Model 1921 before it and entered service from 1928 through 1934. Full-scale production of the type did not begin until 1939 however. A "Navy" model of the M1928A1 existed and this was denoted by the use of a horizontal foregrip, muzzle compensator and swivel slings. Civilian models of the time were noted for their vertical foregrip - then (and now) made more famous by police and gangsters of the 1920s as well as Hollywood icons of the time.

Production of the M1928A1 was handled by Colt's Patent Firearms Manufacturing Corporation in Hartford, Connecticut, and the Savage Arms Company Corporation of Utica, New York, this for the Auto-Ordnance Corporation of Bridgeport Connecticut. M1928A1's saw action with American forces in Nicaragua and were also utilized by the US Coast Guard for a time as well as other home guard and second-line units.

By the time World War 2 came to America's door, the M1928A1 proved too expensive to produce in the large quantities needed. As such, the M1 and M1A1 appeared as relatively inexpensive alternatives to the complicated and expensive M1928A1. Savage Arms Corporation was already manufacturing the M1928A1 at its plant and needed to push more out the door with Lend-Lease orders coming in. As such, the M1 was developed to provide for a better mass-production alternative.

M1 (or "Submachine Gun, Cal. .45, M1 Thompson") was simply a redesign of the expensive M1928A1 models in an effort to simplify and, more importantly, lower production costs. It also featured a simple blowback firing action and offered up modes of fire in semi- and full-automatic. The bolt-handle was moved to the right hand side of the body as opposed to the top of the weapon. The sights were further simplified and the muzzle compensator was removed altogether. A 20- or 30-round detachable box magazine could be used (the 50-round drum was dropped) and the rate-of-fire hovered around 500 rounds-per-minute. Ammunition was the .45 caliber slug. The M1 also featured a permanent buttstock as opposed to the detachable version as found on the M1928A1. The firing pin, however, was as in the M1928A1 and spring-loaded. The rear sight was of a fixed aperture type.

The M1A1 was a slightly revised and improved version of the M1. Its firing pin was now being machined (fixed) to the face of the bolt and replaced the hammer of old essentially making it a "virtual" blowback system. Beyond that, it maintained much of what the M1 a successful weapon. It became the last military Thompson submachine model to be produced.

Small numbers of "European" Tommy Guns were produced by Birmingham Small Arms Company (BSA) of England under the designation of BSA 1926. These appeared in the 7.63 Mauser and 9mm calibers but found very few in the way of purchases.

The Verdict

In combat practice, the M1/M1A1 series proved an overwhelming success. Users noted the weapons reliability in even the most grueling of combat settings and the ability to put much "heat" onto a target was second to none. Its A .45 ACP cartridge proved a more-than-capable manstopper and the handling capabilities were very user-friendly. Though the British Sten series and the M3 "Grease Gun" were both cheaper implements charged with replacing the M1 Thompson, many operators preferred their reliable and older weapon over the new ones being issued. Production of the M1/M1A1 would continue on into 1945. The US military dropped all use of the Thompson in 1971. putting an end to some 33 years of faithful service.

Thompson Nicknames

During her operational days, the M1 Thompson garnered such nicknames as the "Trench Sweeper", "Chicago Piano", "Chicago Typewriter", "The Chopper" and the "Trench Broom". However, it is perhaps known best as the "Tommy Gun".

It should be noted that the Tommy Gun was also utilized by the IRA, acquired via supporters within the United States, and used in the Irish War of Independence (1919 through 1922) and Civil War (1922 through 1923).

Content ©MilitaryFactory.com; No Reproduction Permitted.
The physical qualities of the M1 Thompson (Tommy Gun). Information presented is strictly for general reference and should not be misconstrued as useful for hardware restoration or operation.
813 mm
32.01 in
O/A Length
267 mm
10.51 in
Barrel Length
10.58 lb
4.80 kg
Blow-Back System
.45 ACP
20- or 30- round box; 50-round drum
flip-up adjustable rear sight.
Performance specifications presented assume optimal operating conditions for the M1 Thompson (Tommy Gun). Information presented is strictly for general reference and should not be misconstrued as useful for hardware restoration or operation.
656 ft
199.9 m | 218.7 yds
920 ft/sec
280 m/sec
Muzzle Velocity
Notable series variants as part of the M1 Thompson (Tommy Gun) Submachine Gun (SMG) family line.
"Persuader" - Experimental Model; belt-feed; appearing in 1918.
"Annihilator" - Box-fed from 20- or 30-round magazine; developed in 1918 and 1919.
Model 1919 - 40 examples produced; 1,500 rounds per minute, cyclic; most without buttstocks; sans front sights; Colt .45 caliber
Model 1921 - Initial Quantitative Production Models; 15,000 produced; 800rpm.
Model 1923 - .45 Remington-Thompson cartridge; forearm attachment; bipod; bayonet lug.
BSA 1926 - Export Attempt; limited production.
Model 1927 - Based on the M1921 but fitting an open-bolt and semi-automatic fire.
Model 1927A3 - Semi-automatic, .22 caliber version; production by Auto-Ordnance of West Hurley.
Model 1927A5 - Semi-Automatic Pistol Version; .45ACP caliber; aluminum reciever.
M1927A1 TA5 - Kahr Arms Designation of M1927A5.
Model 1928 - First quantitative military model; based on the Model 1921; lower rate-of-fire.
M1928A1 - revisions to horizontal forend; military-type sling; 20- or 30-round box magazines or a 50-round drum compatability; 562,511 examples produced.
M1 - Simplified Thompson; reduced rate-of-fire to 600-700rpm; blowback operation; charging handle relocated to side of body; flip-up rear adjustable sight; new 30-round magazine.
M1A1 - Low-cost production model; simplified firing pin; stadardized 30-round magazine.
Kulsprutepistol m/40 - Swedish Designation
Global customers who have evaluated and/or operated the M1 Thompson (Tommy Gun). Nations are displayed by flag, each linked to their respective national small arms listing.

Contractor(s): Savage Arms Corporation / Auto Ordnance Corporation - USA
National flag of Australia National flag of Canada National flag of China National flag of New Zealand National flag of the Soviet Union National flag of Sweden National flag of the United Kingdom National flag of the United States National flag of Vietnam

[ United Kingdom; Soviet Union; Canada; Sweden; United States; Australia; China; South Vietnam; North Vietnam; Bosnia; New Zealand ]
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Design Qualities
Some designs are single-minded in their approach while others offer a more versatile solution to requirements.
Some designs stand the test of time while others are doomed to never advance beyond the drawing board; let history be their judge.
Going Further...
The M1 Thompson (Tommy Gun) Submachine Gun (SMG) appears in the following collections:
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