Originally Posted by smoore

There is something to be said about a lower power cartridge than a magnum, collateral damage.

Hell, you could use a .44 magnum but what happens when you miss? That thing is going somewhere. Consider that in home defense you're typically dealing with an unarmored assailant. You don't want rounds going willy-nilly around your neighborhood. .45 and .40 are heavy and slow, the energy is ablated quickly when the bullet encounters something... anything.