Earlier quoted context omitted.
Cough... five comments and no one wonder about the possibility of shooting at drones with this rifle?
Impractical. The effective ceiling of an MQ1 Predator is 25,000 feet, which approximates to 4.5 miles. The effective range of a Barrett M82 (50 Caliber rifle) is approximately 6,000 feet, and that's not shooting straight up. Point blank (which, despite the common vernacular meaning 'really close', actually means 'the range of the bullet before you have to adjust for elevation') is 1500 feet, past that, gravity begins…
25000 feet = 7620m, which approximates to 7.6 km ;)
6000 feet ~= 1800m
1500 feet ~= 450m