There is gunfire, there are echoes, and there are bullet impacts, and more echoes, all of which also make plenty of noise.
The tinfoil hat stuff is comical...
Tin foil hat stuff is being actively encouraged by the lack of any information. If the idiots running this clusterfark wanted to stop tin foil hat stuff, they could at any time by giving the people something to go on. I find myself wondering what is going on with this shooting and investigation.
I operated a privately-owned gun range, and if the audio/video is accurate, it's a no-brainer. Listen to the primary shots, listen for the echoes, and then listen to the shots that are fired in the direction of the camera. They don't match. It sounds like two different firing positions. And, those bullet strikes that you think are are striking concrete, won't make that loud noise at that given angle. They WILL make that type of noise striking people.