The problem is that if CRS 18-1-704.5 (the "Make My Day" law) applies, subsection 3 of that statute precludes charges and a trial (i.e. prosecution):

"(3) Any occupant of a dwelling using physical force, including deadly physical force, in accordance with the provisions of subsection (2) of this section shall be immune from criminal prosecution for the use of such force."

Even in cases where a DA files charges, the statute can be / is cited in pre-trial motions, where it's left to a judge to decide whether to go forward. In such cases, it's an "immunity defense". If a defendant (called a "would-be suspect" in the article) can establish by a preponderance of the evidence that he acted according to the provisions of the statute, there will be no trial.

Of course, it's also an "affirmative defense" that can be used at trial before a judge or jury.