Is it like this
http://pic50.picturetrail.com/VOL480.../396102423.jpg
http://pic50.picturetrail.com/VOL480.../396102422.jpg
If it is its not a 25mm Aden its a 25mm KBA naval gun round (http://www.youtube.com/watch?v=eFXYGLkB5Kw). Green case and blue tip marked TP BMO 12-88 (More infor on it in Janes Ammunition Handbook)
This is the other version that doesnt require a man sat in it http://www.youtube.com/watch?v=UaEpI...eature=related . Notice the rounds feeding in the belt system