Swedish Paratrooper Prototype: AK Fm/57

Published on July 30, 2025
Duration: 10:51

The AK Fm/57 was a Swedish paratrooper prototype rifle developed in the late 1950s, based on the Ljungman AG-42 but modernized with a short-stroke gas piston and folding stock. Despite being chambered in 6.5x55mm, it was designed for the eventual 7.62 NATO transition. It competed in trials against foreign designs like the G3 and FAL but was ultimately unsuccessful, with the G3 being adopted as the AK4.

Quick Summary

The AK Fm/57 was a Swedish paratrooper prototype rifle based on the Ljungman AG-42, modernized with a short-stroke gas piston and folding stock. Despite being designed for a 7.62 NATO transition, this prototype remained in 6.5x55mm Swedish caliber and competed unsuccessfully in 1957 trials.

Chapters

  1. 00:00Introduction to the AK Fm/57
  2. 00:53Design and Development by Eric Wallberg
  3. 01:40Swedish Rifle Trials Context (1957)
  4. 02:47Stock and Grip Features
  5. 03:21Receiver Markings and Dating
  6. 05:41Gas System and Caliber (6.5x55mm)
  7. 08:03Internal Bolt Carrier Mechanism
  8. 09:26Trial Conclusion and Legacy

Frequently Asked Questions

What was the Swedish AK Fm/57?

The AK Fm/57 was a Swedish prototype automatic carbine developed in the late 1950s for paratrooper use. It was based on the Ljungman AG-42 design but featured a modernized short-stroke gas piston system and a folding stock.

What caliber was the AK Fm/57 prototype?

Interestingly, this specific AK Fm/57 prototype was chambered in the traditional Swedish 6.5x55mm caliber, even though it was designed during a period when Sweden was considering a transition to 7.62 NATO.

What unique feature does the AK Fm/57 bolt carrier have?

The AK Fm/57's bolt carrier contains a unique internal sheet metal spring. This spring applies downward pressure on the bolt, likely to ensure it remains securely in battery during the rifle's cycling process.

Did the AK Fm/57 win the Swedish rifle trials?

No, the AK Fm/57 did not win the Swedish military rifle trials. The trials ultimately led to Sweden adopting the Heckler & Koch G3, designated as the AK4, in 1964.

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