Vast number of American gun owners are ignorant of their own weapons? And the vast majority of elitist anonymous cowards don't know what they are talking about. Moron.
A Brit who knows his guns is about as rare as a tea drinking American, and it's a pleasure to meet one. I own several weapons of various calibers but none would reach more than one or two hundred feet with any sort of accuracy, and then only against a stationary target. The best option would be a semi-automatic shotgun firing rifled slugs along the lines of a Saiga 12. But then there's the issue of gravity and a spinning solid mass. Shotgun shell shot will fall harmlessly to the ground; not so a spinning bullet fired on a parabolic trajectory.
Aside from safety issues, the legality of the ownership of the airspace above your property has been pretty much determined since the days a century ago when farmers claimed ownership of the air above their farms all the way to the heavens. While an American property owner owns the ground below her feet down to the core of the planet, a reason why fracking is much more popular here than it is across the pond where property owners do not own the mineral rights below ground, she only owns the air above her property for as high as she can reasonably use. That usually means 100-300 ft max.
Law-abiding gun owners such as myself may entertain such flights of fancy as shooting down drones, but none of us are going to take an AK-47 and spray and pray at a drone delivering Anon Coward's anal beads. Not only do we understand the damage a 7.62mm round can do and never shoot in the air with a rifle or handgun, we also know the law.