I've seen rubber bullets... hit a spit 15 times with 20mm, he loses his flaps. Hit a spit 10-15 times with 20mm, no damage. etc. Rubber bullets, as I understand it, is when you see hit sprites but they result in no damage. As far as I know, that is a connection issue where you send out a packet that says "Hey, I shot the HELL outta that spit", but it gets lost in the mail so the spit flies merrily along.
Never completely MISSED at 125 yards though, that'd be something to see.