So from what I gather, he shot at them fleeing the scene, and it hit the back of the truck. So from that, one of the suspects suffered a wound to the face. I'm assuming it was the side of his face, by what he said, in that he never shot at them from in front of the truck.
I'm not a lawyer, but from what I gather in the State of Colorado, he's sadly in trouble. Obviously because they were fleeing the scene. The "Make My Day" law doesn't protect him in this case. Unless I've missed something.
18-1-706 - Use of physical force in defense of property. A person is justified in using reasonable and appropriate physical force upon another person when and to the extent that he reasonably believes it necessary to prevent what he reasonably believes to be an attempt by the other person to commit theft, criminal mischief, or criminal tampering involving property, but he may use deadly physical force under these circumstances only in defense of himself or another as described in section 18-
18-1-705 - Use of physical force in defense of premises. A person in possession or control of any building, realty, or other premises, or a person who is licensed or privileged to be thereon, is justified in using reasonable and appropriate physical force upon another person when and to the extent that it is reasonably necessary to prevent or terminate what he reasonably believes to be the commission or attempted commission of an unlawful trespass by the other person in or upon the building, realty, or premises. However, he may use deadly force only in defense of himself or another as described in section 18-1-704, or when he reasonably believes it necessary to prevent what he reasonably believes to be an attempt by the trespasser to commit first degree arson.