The shooter actually had a Sig Sauer MCX according to reports. Not sure if it is semi-automatic, automatic, an assault rifle or whatever else, but it sure does fire plenty quick.
[video]https://youtu.be/zmyluo3aT0Y?t=6m11s[/video]
I'm not exactly a pro at posting here, but if that doesn't start at around 6:10, please fast forward until you get there. It's a very long video and that is the exact spot where the demonstrator starts shooting quickly.
ETA - CARIIS beat me to it with the commercial, but this video builds off of that and really shows the gun in action.
I've seen this story as well, and it seems to me what is implied is that the Pulse shooting is the most deadly shooting by a single civilian gunman in US history. Perhaps having to put "Pulse Shooting Most Deadly Mass Shooting Perpetrated by a Lone, Civilian Gunman in History of US" each time might possibly take up the entire screen with all the exactness included. Of course other shootings perpetrated by the military and the government hundreds of years ago against Native Americans would have been way worse because of the idea of Manifest Destiny etc, but they were not by a single gunman so it's a different situation.
I think you are 100% correct, and my money is on The Daily Fail or TMZ.
Speaking of TMZ.. nevermind, because I don't think it's allowed to link so I'll wait until it's reported on a mainstream media site.