Here's the parts that matter:
(a) A person is justified in using deadly physical force upon another person if the person reasonably believes that the other person is:
(1) Committing or about to commit a felony involving force or violence;
(2) Using or about to use unlawful deadly physical force; or
(3) Imminently endangering the person's life or imminently about to victimize the person as described in 9-15-103 from the continuation of a pattern of domestic abuse.
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(B) However, a person is not required to retreat if the person is:
(i) In the person's dwelling or on the curtilage surrounding the person's dwelling...
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(1) "Curtilage" means the land adjoining a dwelling that is convenient for residential purposes and habitually used for residential purposes, but not necessarily enclosed, and includes an outbuilding that is directly and intimately connected with the dwelling and in close proximity to the dwelling
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Boogie fucked up. You can only use deadly force to stop a violent crime or felony in progress (nome was). You can't go outside to confront someone and then shoot them. That isn't how it works. Also no cop is going to say "If he stops foot on your property you're good to go blast him away." That's retarded. Especially considering the law as written doesn't do that.