Need some guidance, started the campaign, got the treat axis, locked on a mig21, I cycled through "all" of my weapons and nothing happens..?
Happened to me too.
Try cycling radar mode and go RWS, re-acquire target again.
When target is in range, HOT Trigger light on front dash will be lit up, now you can fire missiles.
Make sure you are in STT mode when operating AIM-7.