Oh, it gets even better. I was thinking about volume of fire and damage because of this post. Consider the difference between hitting the aircraft at say, 10 feet off the muzzle, and hitting it at 300 yards after the rounds have had a chance to slow down a whole bunch.

Also consider the difference in impact between flying away from the firing plane, flying at a 90 degree vector to the firing plane(no change in closing speed) and flying directly toward the firing plane. All of this is modeled. Closure rate affects damage.
The volume of fire needed at different ranges and differing angles of attack is going to vary widely.
It's a nice thought, but I think it's just not as meaningful as you would like it to be.
Wiley.