Did you ever see anyone in a movie or on television have an accident with a gun? Of course, that never happens in real life, either. Or how about this: the person shooting either runs out of ammo or it jams, which seems to happen a lot, too, and he just throws the gun away, not necessarily at the other guy. Only the bad guy does that!
As far as sound goes, most, but not all, of the audio in movies is added after the fact because of technical reasons. Mostly it is just voices that are recorded. It took a while before they got that worked out, too. But that's why car engines often don't sound right and why lots of other sounds are never heard.
Now and then you will learn something that is surprising. Elmer Keith once mentioned something about how movies give a false idea of the capabilities of guns, particularly handguns. He said something about how hits are made by someone off camera using a rifle. I didn't believe him. Well, he was sort of correct, though I have no idea how he came by his information. I saw a photo of such a thing being filmed. The scene was probably being filmed in the 1940s or 1950s.
The scene was a close up. The camera and the actor were just a yard or two apart. As I recall, the actor was down on the ground (this was a Western). The camera was screened or protected by something like plexiglass. A man with a rifle was shooting into the ground just a few feet away, presumably to create the effect of a bullet striking the ground. I don't recall where I saw the photo but it was a very surprising thing. I doubt it would have been in a B movie because they were made on the cheap and they wouldn't have gone to the trouble. These days, the effect would have been achieved in other ways, of course, and there's always the special effects that weren't even around 30 years ago. I must try to find that scene.
In older movies one does see empty cases being ejected from lever action rifles but these days you don't even see that.
Shoot low, sheriff. They're riding Shetlands!
Underneath the starry flag, civilize 'em with a Krag,
and return us to our own beloved homes!
Buy War Bonds.