I am starting to feel inclined this way too, he was definitely using a big gun, but as for what is was exactly I couldn't tell you, but I assume, much like the tommy gun some big guns like miniguns etc might be capable of repeated bursts, or possibly it just glitched out in the moment and overfired (leaving him at a large minus AP) who knows really.
The main thing is that it does seem legitimately possible
So it was a good death.
I just thought I tack on for the sake of a footnote ZBSDennis was on our faction at the time of this, he had apparently killed 2 others and also assisted in the killing of the person I was with, so watch out for that guy.. That guy who I noticed is in the top ten server PKers >.<