The C42 was a prototype assault rifle designed and manufactured by Swiss firearms company W+F Bern.
The Swiss Army was trialing new weapons and cartridges in the late 1970's to replace the aging StGW.57. Among the trial rifles was the C42, a 6.45x48mm assault rifle with an unusual layout. The trigger guard was enlarged to facilitate for thick cold-weather gloves. Different variants were produced, including carbines, bullpup models and 5.6mm models. The C42 was ultimately beaten by the SIG 550, which was a much more practical choice of service weapon since it was chambered for the already-popular 5.56 round.