Even the A10, with its 30mm Gattling cannon in the nose does not stop flying when its firing.
Granted it may slow a bit, but it doesn't fall out of the sky.
What you are asking for is modeled, its just the effect is smaller than you think it should be.
So your not seeing it.
I say it again, go back to the TA, use the .target command, fire single shots, fire them all, show the dispersion cone.
Then reload and do it again with the trigger held down.
You'll see the dispersion cone is clearly larger.
And until you run the test yourself, honestly, carefully, you are not going to believe what anyone else says.
Be scientific, be methodical, prove it to yourself one way or the other.
But have an open mind going in, don't disprove it because you don't believe it can be modeled.