This is what the F-16 carries:
Designation M61A1, M61A2
Type Six-barrel, hydraulically operated 20mm Gatling gun
Contractor General Dynamics Armament Systems
Rate of Fire 6,000 rounds per minute
Effective Range Several thousand yards
OK, so you fire 1 second bursts - that equates to 100 rounds. You are flying at an assumed 500mph or 700 feet per second, which means your rounds land in a box 700 feet long.
Now assume a range of 3,000 yards or 9,000 feet; and say he let off a couple of rounds as he turned away - say at 25 degrees of turn - he could be 4,000 feet off target horizontally, and landing stuff 9,000 feet away. It's all too easy....