I think your statement is incorrect. It should be
"
When I fire Machine guns, you can damn near empty your magazine on enemy aircraft to were there are all kinds of aircraft particles and debris flying through the air and the target keeps on flying."
There are some nice videos on youtube showing P51 ripping off tails with 1 second bursts and to be honest, it's not that difficult. It needs more practice, though, and you got to know when to engage your target and what to set the gun-convergence to. It also depends a lot on what distances you engage the target.
Best way to test it is in the quick-mission builder, setting up 4 friendlies with you and engaging them at given distances. In the replay you can switch to their external views and watch if your tracers are converging in front of the target, behind it or directly into it. If you found the correct value and learn how to judge distances using the crosshair-diameters, you can kill anything with just a short burst - except Tigers, of course.
