22 Jun 2010 26 Jun 2010
The 10 kill streak must be done in the ADVANCED MISSIONS. I did this on The Herd. Get a game with just you and a buddy by voting to kick any randoms. Do this so you can restart if you mess up and you won't be competing for kills.
Pull out your sniper rifle and run down the first stretch of path that is downhill. Scope in and move around so the cliff side is protecting you and start poppin' heads. If you get lucky they will cluster up at a box of explosives near the tent on the right. Use the Marksman II class and you get 20 sniper rounds. If you lose your chain or run out of ammo you both can jump to your deaths to restart.
You must complete each mission once to unlock the advanced missions. In this mode you are required to use expert targeting mode and enemies deal/receive more damage. So unless it's a head shot, the buffalo rifle takes more than one shot to kill. Also it helps to have your Coop partner stand behind you in case you get downed so he can revive you in time to save your chain.
Mounted weapons like the cannon work well as long as your immediate area is clear of hostiles. The Escape and Ammunition provide ample kills on the cannon. The cannons in The Escape are on the hill to the left of Tumbleweed as you ambush which is about 10 minutes into the mission. The cannons in Ammunition are on the Southern Hill and require killing over 20 soldiers to mount the guns. The setup time is much longer than on The Herd so try not to make mistakes if you choose the cannon route.