It absolutely sounds like a automatic weapon firing.Listen to what is for sure full auto.Did he honestly have automatic weapons? Do you have a link to something stating that as fact? The reason I ask is that in order to get an automatic weapon, it requires a significant jumping through hoops. Additionally, firing an automatic weapon from that distance wouldn't be very effective.
https://www.bing.com/videos/search?...4D4F485BCD45D45E65704D4F485BCD45D45&FORM=VIRE
Then listen to this sound of the shooting. No doubt in my mind it's full auto. Either he obtained it illegally, or converted it himself. Doesn't take a weapons specialist to do it. Far as accuracy goes, he didn't need to be accurate. He was shooting fish in a barrel. All he needed was volume of bullets and he had that.