Some states, at least most sane states, consider a night-time invasion of an occupied dwelling an affirmative defense if the homeowner uses lethal force in response, even if the intruder isn't armed, or apparently armed.
If someone is willing to break into a home during a time when it is highly likely that it will be occupied, the presumption is that they constitute an immediate threat to life and limb and that threat can be met with deadly force.
Some states still have the "you must first retreat" restrictions on use of deadly force, even during a night time invasion.
"The gift which I am sending you is called a dog, and is in fact the most precious and valuable possession of mankind" -Theodorus Gaza
Baby Jesus cries when the fat redneck doesn't have military-grade firepower.