Chain kill? That's actually easy to get. I have about 13 of those. No skill is needed if you use the class I give you.
Map / Gamemode
(When ever the come around the corner of their house theres about 5, spray them down get the others from the other side. Continue these steps til' you get 8+ kills.)
* MK-48 or LSAT
* Target Finder; FMJ, Stock (Primary Gunfighter)
* Lightweight; Toughness; Dextirity
* Concussion x2