The Karabiner Modell 1931 or K31 straight-pull bolt action rifle, chambered for the 7.5×55mm Swiss cartridge or 7.62×51mm NATO. It was the standard issue rifle of the Swiss armed forces from 1933 until 1958. It has a 6-round removable magazine that can also be fed by a clip from the top of the receiver.
Its safety is a large ring-shaped safety on the back of the bolt cocking piece.
This tag implicates bolt_action and rifle (learn more).