I'm not positive that 15 yards is the maximum distance for dart guns. I'm almost certain that there are darts with longer ranges. The rhinoceros is a dangerous animal. One of Africas Big Five. I've had the fortune of being on Rhino dart hunts. I've also been in very very close quarters with different rhinos. I had one situation where I was only 7' feet from a rhino. Was it a very dangerous situation, of course it was. If he charged would I have been shooting, probably not. If that same rhino were to charge and I had a client, a cameraman, a veterinarian, a tracker, and God knows what else behind me would I have shot, probably.