Quick question: what does a plane have that a bullet lacks?


Answer: an engine to maintain its speed.


Bullets start slowing down the moment they leave the muzzle (alright,
just slightly *after* they leave the muzzle), while the aircraft that
fired them can maintain its speed.

But in this case there is no air friction to "slow" the bullet.
It leaves the gun into still air, and so if the bomber is accelerated a
bit by the gun's recoil, its muzzle velocity is a bit less than the
airplane's velocity and so will move "forward" a little as it falls.


Dan