I'm trying to complete the Abstergo challenges for Black Flag and one of them of course is the 7 Kill Streak challenge. I simply cannot complete this one for some reason. I always take hits during the sword fights as three or so enemies attack me at once and one of them always gets a hit in on me which ends the streak. It doesn't seem like you receive credit for this challenge when using pistols as that has failed for me every time. I have tried using sleep darts and then assassinating them while asleep but that doesn't work.
Does anyone have any tips or strategies to share? Is there a particular sword set that works best? Can it be done with pistols and I've just been screwing it up? I am open for just about any suggestion. Perhaps some combination an air assassination with some smoke bombs and then using swords for the last five? Something else? Thanks.