I actually have that Discovery documentary you're probably refering to and they have indeed proven that it "may" have been possible for Lee Harvey Oswald to hit Kennedy from the building he was in, if he would have been an expert hitman.

Furthermore, the documentary shows that spots like the bridge and the drain were pretty much impossible to hit the president and ends with saying that they have disproven every theory.

Ironically, they don't say anything about the most infamous spot, the grassy knoll, as if they weren't able to disproof that.

And that's just the number one place which would have been probably the best spot to hit the president. And there are plenty enough signs that shots came from there.

One things I just can't get out of my head. When you watch the Zapruder film you clearly see the president being hit at the front side of his head first instead of from the back. So called expert can say what they want, they can't convince with anything that he was hit from the back of his head first.

For me, this is the most convincing sign that there were more shooters than only Oswald.

And if it was a conspiracy, they most definitely would have used more than one assassin at multiple locations with the best spot probably being the grassy knoll.

I tend to believe in the theory that Oswald was in fact one of the assassins, probably a decoy, and there was a backup team at the grassy knoll to finish the job if Oswald missed.

I believe that Oswald did hit Kennedy with the so called "magic bullet", which is shown in the Discovery documentary. But the fatal shot probably came from the grassy knoll.