i don't know about non-american jets, but on those such as F16s and F22s when you are firing AMRAAMS the HUD will tell you the probability of kill of your missile which depends on your altitude (dense air at low altitude will slow the missile reducing the probability of kill), weather conditions, speed of the jet firing that missile and other things. as there's no first person at the moment, for jet attack there could be this circle coming out on the screen somewhere only then a target Is locked and when we are ready to fire. if the circle Is big, the probability of kill Is high, if the circle Is small the probability of kill will be low.
the three pics i put here are from the Grinnelli F22 model for DCS and shows the circle im talking about in the middle of the HUD.