During the Iraqi war, there was a lot of anti-aircraft fire going on, which I assume was large bullets (shells?). Anyway, a lot of those missed (or all of them). How far do they travel and where do they end up?
If they land in the desert and no one is around to hear, do they make a noise?
Depends on the trajectory and speed of the projectile. They most often fall on the ground…
Of course, they create a shock wave that becomes “noise” if and when some auditory nerve connected to a brain tells the brain that it picked up the shock wave. A recording device could also record the event, however it wouldn`t technically be a “noise” until someone listened to it.
It depends on how you define “noise.” If noise is the air vibrations that the impact makes, then yes the shell makes noise. If noise is the auditory signals that the ear sends when it detects those vibrations, then no it does not make any noise.
Aren’t you glad you asked? 
my brain hurts.
ouch.
Scotcho
The larger calibre guns have exploding shells, the small fragments wouldn’t travel far from the place they exploded above Baghdad.
IIRC at Pearl Harbor 3 american civilians died from AAA fire that hit their car.
I adopted my last bullet from the pound.
That part about falling and whether or not it would make a noise was a joke… you know, the tree thing… i was more curious about the distance and damage it would cause… i was thinking people would think that last question was funny… sorry.
AA fire is usually explosive shells. They are commonly fused to explode at either a preset altitude or in proximity to a target. IOW, they are not coming down as solid “bullets”. If the fusing fails, then you can get a live round falling to earth, but this is not normal operation.
Ha, Ha, we edged you into apologising. Our answers were a jestful response to your playful question.