I am suprised that the gun works against the dreaded "Green-heads." I have frequently swatted the little buggers (a good hit too!), they fall, wait a minuite, shake it off, fly back and bite me again! I have since learned that when defending against them that the job isn't done unless I see guts, or I pull a wing off.
My wife thought I was sadistic, until she had it happen to her a couple of times. Now, she's a sadist too!