After World War Two the Swiss needed a new self-loading military rifle to replace their K-31 bolt actions. Two major design tracks followed; one being a roller-delayed system based on the G3 at SIG and the other being a derivative of the German FG-42 at Waffenfabrik Bern. Bern, under the direction of Adolph Furrer, had been experimenting with intermediate cartridges since the 1920s, and they used this as a basis to develop an improved FG-42 using an intermediate cartridge (7.5x38mm). The program began in 1951 and went through about a half dozen major iterations until it ultimately lost to the SIG program (which produced the Stgw-57).

Today we are looking at one of the later steps in the Bern program, the WF-54. By this point the intermediate cartridge had been discarded in favor of using the standard Swiss GP11 (7.5x55mm). The overall design was a bit simplified as well. The Bern program would continue for two more years after this rifle before ultimately losing out to the SIG 510 for Swiss military adoption.

Many thanks to the Royal Armouries for allowing me to film and disassemble this rifle! The NFC collection there - perhaps the best military small arms collection in Western Europe - is available by appointment to researchers:
https://royalarmouries.org/research/national-firearms-centre/

You can browse the various Armouries collections online here:
https://royalarmouries.org/collection/