I understand that まま can be used in order to convey that something doesn't change, or to express lack of change, although in this sentence, I'm not quite sure what it is trying to convey.
目はライフルの照準に合わせたままで、こっちは見ていない。
I have a feeling that まま is being used to convey that the girl doesn't turn to face the protagonist in this situation, as she is looking down the scope, with こっちは見ていない being (roughly, I think): so this way/in this direction (due to this) she hasn't seen me (the protagonist). I'm not too sure, thanks for any help.