Bryan McAllister’s personal reference notebook
July 27, 2026Short & citedBlog
Civic Viewpoint.
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Kept by Bryan McAllister — short guides, clear facts, and the Canadian angle when it matters.
Civic Brief • Weapon

Tommy Gun

The Tommy Gun is a common nickname for the Thompson submachine gun, an American selective-fire submachine gun developed by John T.

Updated July 27, 20261 min readCited sources

The Tommy Gun is the common nickname for the Thompson submachine gun, a selective-fire weapon developed in the United States after World War I. It became infamous for its use by gangsters and police during the Prohibition era, and later served in World War II.

Design and development

The Thompson submachine gun was designed by Brigadier General John T. Thompson in the late 1910s as a portable automatic firearm for close combat, particularly trench warfare. It was chambered in .45-calibre ammunition and used either drum or box magazines. The weapon was blowback-operated and selective-fire.

Use in crime and law enforcement

During the Prohibition era of the 1920s and 1930s, the Tommy Gun became notoriously associated with organised crime, including gangsters such as Al Capone. Its distinctive sound and firepower also made it a tool for law enforcement and federal agents, cementing its place in American public culture.

Military service and legacy

Though it missed widespread use in World War I, the Thompson saw substantial service in World War II, valued for its durability in close-quarters fighting. Its iconic status persists under nicknames like “Chicago typewriter” and “trench broom,” and it remains a symbol of 20th-century firearms history.

In short

  • The Tommy Gun is a nickname for the Thompson submachine gun.
  • It was developed by John T. Thompson in the late 1910s.
  • It became notorious for use by gangsters during the Prohibition era.
  • The weapon also saw extensive military service in World War II.
Canadian angle

The Tommy Gun is part of broader North American firearms and crime history, and it is often referenced in Canadian museum collections, war history, and popular culture discussions of 20th-century firearms.

Quick questions

What is a Tommy Gun?
A Tommy Gun is a nickname for the Thompson submachine gun, an American automatic firearm developed in the late 1910s.
Who invented the Tommy Gun?
It was developed by Brigadier General John T. Thompson, an American Army officer.
Why is it called the Tommy Gun?
“Tommy Gun” became a popular colloquial name for the Thompson submachine gun, alongside “Chicago typewriter” and “trench broom.”

Sources

  1. Wikipedia — https://en.wikipedia.org/wiki/Thompson_submachine_gun
    Supports: Nickname, development date, designer, action type, and alternate names.
  2. Encyclopaedia Britannica — https://www.britannica.com/technology/Thompson-submachine-gun
    Supports: Designer, ammunition, magazines, Prohibition-era notoriety, and historical context.
  3. Popular Mechanics — https://www.popularmechanics.com/military/weapons/a25414/tommy-gun-thompson-submachine/
    Supports: Popularity in popular culture, wartime service, and nickname usage.
  4. Warfare History Network — https://warfarehistorynetwork.com/thompson-guns-curious-history-from-world-war-i-to-world-war-ii/
    Supports: Origins as a World War I trench weapon and development history.
  5. Coffee or Die — https://www.coffeeordie.com/article/tommy-gun
    Supports: Broad historical use by military, law enforcement, and criminals.