High Quality Content by WIKIPEDIA articles! The C42 was a prototype assault rifle manufactured by W+F Bern of Switzerland as an entry in a competition for a new Swiss Army service rifle (Truppenversuch). It was chambered in 5.56x45mm NATO and 6.8mm SPC in and designed in conventional as well as bullpup layouts. As the competition was won by what became the SIG SG 550, the C42 did not see mass production.