@isaackuo @cstross The thing you're trying to counter is the reconnaissance. (Whether it's on "massing for assault" scale or "is that $POLITICAL_FIGURE?" scale.)
For that, you most want to break the comms loop; you next want to destroy the drone beyond its range of resolution.
Kinetic solutions against individual drones need more range than a shotgun because the range of resolution is greater than shotgun range. (Hence 30mm smart rounds as the reflexive solution.)
@graydon @cstross
Heavy shotguns are a countermeasure against enemy killer drones/bombs, not looker drones.
If you want to take out lookers, anti-drone drones seem to be the most promising approach for now. A 30mm smart round could easily be more expensive than the target, and also more expensive than an anti-drone drone.