There's no good way to do that. You'd be trying to hit a moving target from a couple hundred feet away in probably windy conditions and maybe limited visibility, and a bullet could pass between the quadcopter's arms without doing any damage to it.
I am guessing that it's an airplane rather than a quad, because they reported it to have a 4 foot wing span. I guess you have a point, I never shoot anything from more than 80 yards, so it might be impossible. Maybe they need attack drones of their own after all :)
Jamming a frequency would cause more of a problem, because now you have an /uncontrolled/ four foot across aircraft flying in restricted airspace. With a controlled craft, you could at least get on bullhorns and try to yell at the idiot flying the drone to stop.
The more advanced models -- the ones more likely to be flown by someone in that situation -- have an automatic return-to-home function that kicks in if it loses the connection to the radio.
On the cheaper models, I'd expect it to simply crash within a minute or two. But it would be interesting to test that.
