BOR invented a completely new class of weapons nobody had ever heard of - this “heavy weapons” thing.
Oddly enough, the AR that was used in the movie shooting is a "light weapon" by anyone else's definition. Had joker-freakboy used a conventional battle rifle (like the gunman in Norway did) casualties would have been much worse.
Also, in all the hysteria over "100-round magazines," notice how no one is mentioning that it jammed early, probabaly reducing casualties considerably?