ok, in the movie stealth, which i know is NOT realistic, the UCAV shoots down a russian air to air missile with his own missile.  i didn't think was realistic/practical/feasible/whatever word you want to use.  but, i was just playing a mission, and i was going nose to nose with a Su-33 about 15nm away, and every time he fired a missile at me, my aim-9's would lock on to and i got everyone of them until i ran out of missiles.  is this realistic?