I think the more salient point is that even though he was armed, an unarmed, unskilled teenager--if his story is true--was able to get the
drop on him even though he was giving chase, mount him, and ground and pound him until his only recourse was to pull his weapon and shoot the kid point-blank.
So, considering his serious skill level, I'm sure he'd do much better squaring off against somebody who is... armed.
Hey, maybe if we gave him a 30-round mag, he'd get the job done. After he's popped off 30 rounds at a school, and still not dropped the guy, I mean: I wonder where all those rounds ended up?
Let's christen that argument the Zimmerman Argument: I need to have 30 rounds because I literally suck that bad you need to give me 30 chances to take somebody down with a
firearm.