A good way to get a lot of kills is to go prone using an M107 sniper (1 shot kill) with a view of a high traffic area - preferably, very far away. If you're well concealed, you should be able to pick off all the run 'n gunners who are spraying bullets at each other and praying for kills. While these types of players may end up being the team MVP for kills on occasion, they will also always be the team leader in deaths, as well. Remember: short, controlled bursts while kneeling or lying prone will beat the crazy running gunner 9 times out of 10.