To dream of a rifle represents a decision or power that is precise. Perfectly aiming for the problem or something you don't like.
A rifle often appears in dreams when you are telling someone else exactly what their problem is.
Example: A young immigrant boy had recurring nightmares about a rifle attack. In waking life his entire family was gunned down one by one in his old country. The rifle reflected his horrible feelings about how careful and specific the murder of his family was.