StreakerG 100

You have to kill five enemies in a row without dying yourself.

I did this with the M249 LMG because it has no recoil, and with the Phantom and its lightning shield. Stay in the back row of your team and take cover when you get hit, and when you're safely off the flank, you can use either the M249 or the shield to half-kill the enemy, which counts towards the killstreak. You can also throw a grenade and maybe make one or two kills to start a new life.

If you are in a killstreak, a skull symbol with a number will appear below the killfeed. Hotshot is a good mode for simple series.

If this or any other achievement is not displaying correctly, close the game, restart your console and start the game again. Any missing achievements should unlock when you load the main menu. This should also refresh all achievement bars.

Good luck!