The Swedish submachine gun that became a clandestine tool for US SEALs

Wars & Conflicts · Published 17 October 2026 Swipe more like this →

In short: In the heat of the Vietnam War, the US Navy SEALs relied on a weapon they called the "Swedish-K." It was prized for its ability to fire almost immediately out of the water. This reliable design eventually led to an export embargo and a secret quest for a domestic copy.

Developed between 1944 and 1945, the Carl Gustaf m/45 (or Kpist m/45) was designed by Gunnar Johansson. It was built using sheet metal stamping techniques studied from prominent German, British, and Soviet submachine guns of the era. While it served as the standard Swedish Army submachine gun from 1945 to 1965, its engineering was defined by a straight blowback mechanism and a relatively slow cyclic rate of 550–600 rounds per minute, making it exceptionally easy to control during full automatic fire.

The weapon's design features were highly functional for harsh environments. Its 36-round magazine utilized a unique trapezium shape; this staggered row design was more reliable in sub-zero temperatures and dusty conditions than parallel-sided magazines. Because of its reliability, the basic magazine concept was eventually adopted by several other nations, including France and Czechoslovakia. In Sweden, it remained in service for auxiliary troops until 1986, with the final official users retiring it in April 2007.

The m/45 gained international notoriety through diverse clandestine and conventional uses. During the Vietnam War, US Navy SEALs and CIA operatives used "sanitized" versions—often devoid of markings—to maintain secrecy. The US was so impressed by its performance that when Sweden embargoed arms exports in 1966, Smith & Wesson was tasked with creating a copy (the M76). Meanwhile, the weapon saw licensed production in Egypt as the Port Said and Akaba models, and even appeared in various insurgent groups across Iraq and Central Africa.

General information, not professional advice. Spotted an error? Flag the card or see corrections and complaints.

Intellect Plus is a visual educational discovery platform for exploring fascinating facts and ideas. Brain Food, Not Brain Rot. What is Intellect Plus?

Related

• The Swedish Mauser: A rifle defined by unique geometry and steel
• The Bofors 40 mm gun: A Swedish invention that defined World War II air defense
• The Belgian pistol that changed history through the hands of revolutionaries and world leaders
• The wartime German cartridge that bridged the gap between submachine guns and full-power rifles.
• The Soviet machine gun nicknamed the record player for its unique pan magazine
• Was the Catilinarian conspiracy a genuine threat to Rome or a politician's masterclass in manipulation?
• The soldier defined by a shorter rifle and a heavier armor
• The prison cell where the end of the world was written
• How a Secret Nighttime Betrayal Ended the Siege of Neapolis in 327 BC
• How a wall-building dispute triggered two decades of brutal conflict in ancient Hispania
• How a strategic tunnel ended the Roman conflict with the city of Fidenae
• How India’s industrial guard force evolved into a global security and disaster management powerhouse

More in Ancient & biblical wars · More in Wars & Conflicts · Latest · A–Z · All topics