When they said 'rifle' I assumed it was someone just taking single shots at people. Nobody needs a weapon that shoots like that unless they're in the military. It's shocking that things like that are legal over there.
I suppose the answer will be 'if only the people in the parade had bigger guns...'
They should just make it mandatory to have at least a pistol on you at all times.
If they properly committed it would end all this spree shooting crap