Not all shooting sprees are planned in advance. When they're not, the attacker will use the weapons that are readily at hand.
Which scenario has the capacity to kill more people in the shortest amount of time:
a) Going to a public place where a number of people may be gathered, armed with a handgun and a bunch of clips?
b) Going to a public place where a number of people may be gathered, armed with an assault weapon and a bunch of high capacity clips?
Bonus question: if a person intent on doing quite a bit of harm to a group of people has a HCAW and a handgun, and multiple clips for both, which weapon is he most likely to use first, and why?