You seriously won't be charged for murder in the states for shooting someone with buck shot in your home? Our laws are very different here. Is there no escalation of force requirements in your self defence laws or are you only referring to cases where the intruder is pointing a gun at you?
Isn't the point to not kill them and scare the piss out of them in order to avoid having to deal with the murder charges? I'd love to meet the dude that wants to continue stealing your TV after a couple loads of even bird shot in the back.. Criminals aren't exactly trained soldiers, I'd bet that half the time, even if they are armed, they'd be running as fast as they can at the mere sight of a home owner with a shotgun, loaded or not.