if you see it hit then it hits- the sound just doesn't play every time
I'm gonna have to disagree with this. It may be the way its intended to work, but its not the way it actually works.
During 0.3.1 I was running a mech or tank with AC10 on, I kept shooting at it at point blank range (50-150m) and spent almost all my ammo against a heavy mech and its damage display barely turned yellow.
My ping was at the time in the 150 range, but I find it very hard to consider it lag as I was chasing the mech for several minutes firing almost constantly and could see myself hitting with at least 8 of 10 shots, but in my impression is was only the hits I heard the hit sound from that actually counted as hits.