Discovering the M31 Suomi: A Timeless Submachine Gun

Discovering the M31 Suomi: A Timeless Submachine Gun

Posted by Jacob on Dec 8th 2021

In the world of military surplus, few weapons command the same level of respect and fascination as the M31 Suomi submachine gun. With a history deeply rooted in 20th-century conflicts and a design that has influenced countless other firearms, the M31 Suomi is a prized piece for collectors and enthusiasts alike. Let's dive into the rich history, unique features, and lasting impact of this iconic submachine gun.

A Brief History

The M31 Suomi, also known as the Suomi KP/-31, was developed by Finnish designer Aimo Lahti in the early 1930s. Its name, "Suomi," is derived from the Finnish word for Finland, reflecting its origins and national pride. The weapon was officially adopted by the Finnish Army in 1931, just in time to play a crucial role in the Winter War (1939-1940) and the Continuation War (1941-1944) against the Soviet Union.

The M31 Suomi quickly earned a reputation for its reliability, accuracy, and high rate of fire, making it a formidable weapon on the battlefield. It was particularly effective in the harsh winter conditions of Finland, where other weapons often failed.

Design and Features

One of the standout features of the M31 Suomi is its sturdy construction and exceptional craftsmanship. Here are some key characteristics that set it apart:

  1. Robust Build: The M31 Suomi is known for its solid steel construction, which provides durability and resilience in extreme conditions.
  2. High Rate of Fire: The submachine gun boasts a rate of fire of around 750-900 rounds per minute, making it highly effective in close-quarters combat.
  3. Detachable Magazine: The M31 Suomi originally used a 20-round box magazine, but it is most famous for its 71-round drum magazine, which offered sustained firepower.
  4. Accuracy: Thanks to its long barrel and well-designed sights, the M31 Suomi was more accurate than many of its contemporaries, making it effective at longer ranges.
  5. Ergonomics: The weapon's design included a comfortable wooden stock and an easy-to-use fire selector switch, enhancing its usability in combat.

Influence and Legacy

The impact of the M31 Suomi extends far beyond Finland's borders. Its design and performance influenced several other submachine guns, including the famous Soviet PPSh-41. The PPSh-41 borrowed heavily from the Suomi's drum magazine and overall layout, becoming one of the most widely used submachine guns of World War II.

The M31 Suomi remained in service with the Finnish Army for several decades, and its robust design ensured that many examples survived in good condition. Today, it is a sought-after collector's item, prized for its historical significance and engineering excellence.

Collecting the M31 Suomi

For military surplus enthusiasts, owning an M31 Suomi is like holding a piece of history. When searching for one, here are a few tips to keep in mind:

  • Condition: Look for examples in good condition with original parts. Many M31 Suomis have been well-maintained, but some may show signs of wear from their service life.
  • Documentation: Authenticity is crucial. Ensure the weapon comes with proper documentation to verify its history and provenance.
  • Ammunition: The M31 Suomi typically uses 9x19mm Parabellum rounds, which are widely available, making it easier to find suitable ammunition for display or shooting (if legal in your area).


The M31 Suomi submachine gun is more than just a weapon; it's a testament to Finnish ingenuity and a symbol of resilience in the face of adversity. Whether you're a collector, a history buff, or simply someone who appreciates finely crafted firearms, the M31 Suomi holds a special place in the annals of military history. Its legacy continues to inspire and captivate, ensuring that it will be remembered for generations to come.