According to wikipedia the GAU-22 is supposed to have 1.4mil dispersion. Assuming the bullet doesn't start tumbling that could make for some very long range strafing, my understanding is that the 25mm made it's way onto the AC-130 because the 20mm was doing exactly that, hispeed does that check?. Obviously that doesn't account for kinetic energy.
I guess my thought goes that if we built an airplane around the GAU-22 vice the GAU-8, how much more efficient could the whole thing be? Less weight in gun/ammo means less fuel to burn, less fuel weight means less structure to carry it, etc, etc, etc.
Based on :
I don't think A-X 2.0 stands a chance unless it's kept to the bare minimum required. That's what got me started down this cocktail napkin exercise.