Aim-7 troubles

Since the last open beta patch my Aim-7's seem to miss much more than before. I have track after track of the missile passing very near my target but nothing happens. Shouldn't the missile explode when it detects that it is near the target or does it actually need to impact it? Am I expecting too much from the sparrow?

I have noticed the very same thing.... most recently in the strike fighter mission. I never use sparrows though, so I just chalked it up to that being how it is...