Lol i still laughing from ppl in multiplayer who call me noob for :
Killing with gl (well i can understand that)
camping with a sniper in hardcore (maybe even that)
Killing with AA-12 (I think iam the only one who uses this gun)
Killing with Uzi (:/)
Killing with Vector
Killing with melee
Killing with Claymore
killing with trowing knife(:O)
killing with m9 (xD)
They are probably those noobs with Bling Famases.
Anyways you can succeed with any weapon in this game, which is not a surprise.