Hold Your Breath
How To Unlock: Kill 250 people using sniper rifle. (Multiplayer)
For this trophy you have to kill a total of 250 people with a sniper rifle in the game's Multiplayer mode. Sniper rifles are the main weapons in the online mode, so you should get this trophy while going for the 2000 online kills. Remember that only Ranked Kills count towards the total, making this a little harder to complete, but no bother with a little perserverance.