It is possible to "mow down" 30 people in a minute with any number of hi-cap,semi- auto weapons. whats the diff?
Heck, you can do it a lot more efficiently with a Mossberg 500 or Remington 870 pump action shotgun.
And I've seen a guy get 6 shots off in less than 5 seconds using a double barreled shotgun! He had 2 rounds between the fingers of each hand!
Mark