Here we can see the firing mechanism. The top cover is held in place by a thin metal strip which is now broken in to 3 pieces. the botom of this strip goes through a hole in the firing lever which is secured in place by a wire pin underneath it. The firing lever can be seen passing through the brass firing pin which is sprung loaded. Above the firing lever is the safety bar which passes through the tube and out the other side top left. The wire pin needs to be pulled down and the strip holding the cap snapped off to remove the cap.