A safety and dismantling device for a trigger operated firearm of the type which includes an elongated barrel and a slide which is slidably movable relative to the barrel during the loading, unloading and firing of the firearm, the device being characterized in that it includes a lever which is slidably movable relative to the firearm from a `safe` position where the lever serves releasably to lock the trigger against movement in that direction wherein the trigger can cause the firing of the firearm, to a `fire` position where the lever does not so lock the trigger, and to a `dismantling` position;
- the device also including a slide stop which prevents the slide of the firearm from sliding past the stop when the lever is in the aforesaid `fire` or `safe` positions, thus preventing the slide from being removed from the firearm;
- the slide stop being slidably movable relative to the lever in a direction extending transversely to the longitudinal axis of the barrel of the firearm between a first position when the lever is in the said `safe` position, a second position when the lever is in the said `fire` position, and a third position when the lever is in said `dismantling` position, so that when the slide stop is in the latter position the slide stop allows the slide of the firearm to slide past the slide stop to a position where the slide can be removed from the firearm.