Fucked up. I could easily see this happening to someone where the guy grabs a gun and just unloads into the bed killing his gf and then realizing the other guy was a dummy. Life ruined.
M16 hands down. You can have your higher caliber, and you can shoot all around me while I put a full mag of 5.56 into your head and torso. You take care of your weapon and it'll take care of you.