Situation: you're on second floor and see another guy outside at ~15-20 meters away from the building. He's an easy target, plain sight. You target him with your M4 with nice red dot sight. All seems well. You shoot him, yet all bullets land directly in front of you cause wall is blocking your barrel exit somehow. Guy sees you and shoots you down easily, cause upper part of yur body is popping out of the window, and nothing blocks his barrel.