And that is absolutely crap, why should a .50cal reach out 1.5k in a bomber and not in a fighter armed with the same gun ???
They are modeled the same.
At same speed altitude and firing direction the bullets from the same guns have the same maximum travel distance.
For example, use the .target command offline for a quick test. A B-17 at 1k flying 239 mph shooting straight forward will have it's guns register hits at 1080 yards, but not at 1100 yards anymore. If you do the same at about the same speed in a P-51, you will find the same result.
Of course, the higher you go, the further the bullets will travel, and a bomber shooting backwards to fighter flying towards him will have a greater
effective range than the same fighter shooting at the bomber heading away from him.