Snufkin I got this item some time ago and was told that it was an electrically initiated cartridge which was fired to lock the elevators of the V1 missile in the down position. I was not sure of this until I saw the information in the web site www.zenza.se/vw/ . This includes a description of how the missle works and the diagram already posted. I do not know the correct designaion for the component, just thought it was unusual.
Tom,Suppose if you wanted a device to retain a Mills grenade cocked striker using trip wire this object could do it. Would probably mean shortening the striker spring slightly and fitting the cylindrical bit into the striker hole between the shoulders. Just an idea.
Could it be a pressure released striker booby-trap device for an AP mine?