That first, continuous 10-second sting I analyzed consisted of far more rounds (120) than any linear magazine can hold and feed reliably.
FULL DISCLOSURE: I have not yet analyzed other audio. It could be that on that first string he used a weapon that was "not like the others"...
We absolutely don’t have all of the info yet. Reports of multiple firearms including one on a tripod will make this interesting. Since aiming for a target wasn’t part of his plan two could have been used at either the same time or in quick sequence.