In Call of Duty how to kill sniper?

The best way to kill a sniper is to snipe him yourself!

Although this may sound stupid this is the easiest way. Supposing your target is in a sniper post first you must find a place where no-one else is and where you can get a clear shot through to the sniper then use your scope and get him!!!

Sources:I got 3 headshots on the same guy by using this method.