Small, probably stupid tip, but what the hell. There is an almost surefire way to kill drones without needing a firearm. Buy a high-powered laser (>5W). It obviously won’t be enough to take the drone down, but just a fraction of a second of that beam is enough to permanently destroy the camera. The downside is that the beam is very visible so you’d also be giving away your location. Also works on static cameras like traffic cams, number plate readers, …