I'm no ballistics expert, but...
this story seems to have one big,gaping hole in it.
OK, so the storyline revolves around who was shooting at the US Marines - the snipers from several hundred yards away or the snipers and the nearby crowd of protesters. The snipers were obviously using rifles and, as the tape showed, the protesters were firing hand guns.
All they had to do is retrieve some of the bullets to see that the majority of the shots were made by small arms.
And that would have been the evd of the movie.