well my Nurgle Daemon Prince (G'garl Ul'Rhal Scourge of Mortals, Sheppherd of Beasts, Harbinger of Rot) once killed 22 IG conscripts in one turn (nurgle's rot + charge)
thats ManReaper, Nurgles' Rot and Nurgling Infestation playing to full effect!
ill never forget that day. he wiped out a 40-man unit in 3 rounds of combat... course he was shot down my half a dozen plasma guns after killing the last one.