Abstract: A fire arm mechanism for a multi-barrel weapon has a barrel selector for selecting the firing sequence of the barrels on successive pulls of a trigger (34) common to the barrels. The firing movement (arrow 49) of the trigger is transmitted to the release catches (20, 21) of the different barrels by means of a firing push link (27) pivotally mounted on the trigger and spring-loaded in a direction towards the release catches (arrow 48). In order to shift the firing sequence, the pivot axis (32) of the firing push link (27) is displaced transversely of its longitudinal axis so as to be displaced with respect to the release catches (20, 21), such that the firing push link, depending on its angular position, will either first engage the release catch (21) remote from the pivot center (32) or first engage the release catch (20) close to the pivot center.