Some more factoids on the Newtwon massacre. First, the mother owned the guns legally and was a gun enthusiast. Changing the rules on background checks would only have flagged her if the revised rules barred sales to people living with a (non-adjudicated) mentally ill person.
This description of the ammunition from the Times gets us thinking:
The bullets Mr. Lanza used were “designed in such a fashion the energy is deposited in the tissue so the bullet stays in,” resulting in deep damage, Dr. Carver said.
High fragmentation is low over-penetration - it sounds like the mother (assuming she bought the ammo) had made a plausible home-defense choice of ammo for her .223.
Finally, if this tragedy kicks off a real gun control debate I think high capacity magazines are going to be deeply contentious. From the Times:
Adam Lanza still had hundreds of rounds left when he ended his rampage at Sandy Hook Elementary School by killing himself, the Connecticut state police said. Connecticut’s governor had said Sunday morning that Mr. Vance shot himself as the police were closing in, indicating that he may have intended to take more lives had he not been interrupted.
Lt. J. Paul Vance of the state police said that investigators found “multiple high-capacity magazines,” holding about 30 rounds each, for both the rifle that Mr. Lanza used to kill 26 people at the school and for the handguns he brought along, one of which he used to kill himself.
Lieutenant Vance would not say how many rounds Mr. Lanza fired, though he did acknowledge that “numerous magazines were emptied.’
Well, he could have swapped out magazines even if each only held, e.g., ten bullets. Let me just steal this from the comments of the home defense piece:
20 or 30 rounds for home defense? Who the heck do you have invading? Zombies? Oh! Wait! This is G&A! Of course!
Well, now we are talking about the relative risk/return trade-offs in two incredibly improbable scenarios - a school invasion, and a home invasion where ten rounds in the clip (and a magazine swap) would be insufficient but thirty would be enough. And of course we are talking about some grand societal risk/return trade-off; a guy in a remote home in Idaho may really think he needs thirty in the clip and doesn't want to put himself at risk just to improve the odds of schoolkids in Connecticut (or movie-goers in Colorado).
I will add that lots of folks will argue for the classic pump shotgun as the favored weapon for home defense, and my off-hand guess is they hold six to eight shells. That means a lot of people feel safe, or at least "safe enough", with a lot less than thirty.