I can't do a decent search from work as they have filters preventing looking up a lot of shooting sites. Most of this is back of the napkin figuring.
If you were shooting straight up in a vacuum, you壇 get an elevation of 19,460 feet (and zero upward velocity at that point) with a shotgun firing at 1100 fps. Projectiles need to be moving more than 200 fps to get skin penetration. You壇 probably want 3 to 5 times greater velocity to damage plastic or thin aluminum. Which means your effective vertical range is now only 9,560 to 13,760 feet.
But youæ±*e not in a vacuum and air resistance slows shot even faster. If I have the drag coefficients figured properly, the maximum altitude youæ±*e going to get with a single bullet fired vertically is about 7000 when it reaches zero velocity; and maybe 4000 tops for being able to cause damage to a drone. Buckshot decelerates even faster. You might get max altitude of 1000 feet, but effective damage only up to 700 feet. Thatç—´ enough to take out civilian and police grade rotor drones (mini-helicopters). Youæ±*e not going to take out a Predator or Reaper with a shotgun, and youæ±*e unlikely to get a hit even with a .50 cal machine gun in the 2 or 3 seconds of window you have while it buzzes past.
敵unshots can travel as high as 10,000 feet, and the wind takes them in unpredictable directions.
釘ullets fired vertically spend at least 15 seconds in the air, and many hang for well over a minute.
Can falling bullets kill you?, 26 Nov 2013.
"The buckshot typically used in a combat shotgun spreads out to a greater or lesser degree depending on the barrel choke, and can be effective at ranges as far as 70 m (75 yards)."
Combat shotgun - Wikipedia, the free encyclopedia, 26 Nov 2013.
"Most buckshot loads vary in velocity between 1,100 and 1,600 fps."
Buckshot Basics | Shooting Illustrated, 26 Nov 2013.
Best way to stop drones? Hire a lawyer.