I've only got over 2500 kills with the Scar-H, M4A1 Carbine and the UMP-45. I don't use the M4A1 or the UMP at all anymore. I've got a class for...
Box and computer is where all the cool cats hang. :)
Mother Wang XUndiesX
Just go to an area without much activity and change it. Although, as others have said, it's probably easier for you to find one setting that...
Although I can't be bothered looking for a source, I'm sure that they said we can't