I decided to check out this forum because I'm probably going to be moving to Montana in the near future.
It sounds like you guys should steal a couple of our laws from Washington
RCW 9A.16.050
Homicide—By other person—When justifiable.
Homicide is also justifiable when committed either:
(1) In the lawful defense of the slayer, or his or her husband, wife, parent, child, brother, or sister, or of any other person in his or her presence or company, when there is reasonable ground to apprehend a design on the part of the person slain to commit a felony or to do some great personal injury to the slayer or to any such person, and there is imminent danger of such design being accomplished; or
(2) In the actual resistance of an attempt to commit a felony upon the slayer, in his or her presence, or upon or in a dwelling, or other place of abode, in which he or she is.
RCW 9A.16.110
Defending against violent crime—Reimbursement.
(1) No person in the state shall be placed in legal jeopardy of any kind whatsoever for protecting by any reasonable means necessary, himself or herself, his or her family, or his or her real or personal property, or for coming to the aid of another who is in imminent danger of or the victim of assault, robbery, kidnapping, arson, burglary, rape, murder, or any other violent crime as defined in RCW 9.94A.030.