When you fire a missile or anything with a second stage and the target is INSIDE the release range it doesnt release the payload...
I.E.: I have a stinguer size 2 missile with 70mil range, and i wanted to breach the 100mil so i made a size 5 missile carrying 2 stinguer just to boost the range a little bit over 100mil and made the release range as far as the rocket allowed to go wich is about 25mil KM, the problem is if the ennemy is well inside the 25mil like at 10mil the second stage dont release and the missile simply head to the target even if he have a 0 warhead...