Um incase it needs clarfication, AAMG stands for Anti-Aircraft Machine Gun. In other words a HMG (Heavy Machine Gun defined by mount -- large crew or large mount, such as tripods and vehicles) mounting, on a stable platfore (IE Truck, AAA stand, or some other stable/fixed surface).
The essence in which a plane mounted machine gun works relative of a ground-type are very different. Plane mounted guns are subject to three plans of unstable movement. Ground guns aren't. You'd have to be closer than 100 yards in an Air to Air situation to get the same effect as 2000-1500 yards in a ground to air situation.
