[DUMBGRUNT]

GAU-8 Avenger
Effective firing range 4,000 feet (1,220 m)
Maximum firing range Over 12,000 feet (3,660 m)

https://en.wikipedia.org/wiki/GAU-8_Avenger#:~:text=The%20General%20Electric%20GAU%2D8,a%20high%20rate%20of%20fire.

[Steely Tom]

Yeah, but the GAU-8 has a muzzle velocity of over 3000 fps. If you don't count air resistance, assume the round is launched at with the Warthog moving at 200 mph at an altitude of one mile, and the round is fired at an angle of 45 degrees with respect to the ground, you get a distance of 413,411 feet! That's a bit more than 78 miles!

Of course air resistance is a factor, but the depleted uranium rounds that thing fires are mighty dense compared to their cross-sectional area, and the round would spend quite a while at high altitudes where the air is pretty thin (apogee with no air resistance would be a bit more than 107,000 feet). So it might fly an appreciable fraction of that 78 miles.

I think that 12000 foot "maximum firing range" figure is probably more like "maximum range for any practical shot at an actual target."