I can tell you right now its Fully automatic, the definition of which is this:
fully automatic firearms will continue to load and fire ammunition until the trigger (or other activating device) is released or until the ammunition is exhausted.
The activating devide is your mouse button (or rollerball or whatever) and it will keep firing untill it runs out as long as you keep it pressed. Rate of fire is NOT what determins if a weapon is fully or semi auto, its the mechanisum by which it fires.
It may not be clear in the vids, but thats what it is, although technically by todays weapons terminology its more of a autocannon, not to be confused with the 40k version.