Is this a troll? (wait, it's Ann Coulter, of course it is)
The gun I own, a Glock 19, has the dubious distinction of being the weapon of choice in both the Arizona and Virginia Tech shootings. The standard magazine size is 15 rounds, and it's not long or unwieldy at all. Double stacked 9mm magazines can hold a lot of ammo in a small space. A larger 9mm pistol like the Glock 17 or Beretta 92 can hold 17 rounds. The only unwieldy magazine available for Glocks is that ridiculous 33-round one that's like a foot long. That one would be a disadvantage for a spree killer, but a 15- or 17-round one would not.
And the Columbine shootings? Um, one of their guns was a semiautomatic Tec-9 and they had at least one 52-round mag for it.
I do agree that conceal carry laws are a good thing. But come on, what is her magazine size argument about? It's just a crock of made-up shit.