One thing that many people don't understand when playing an FPS game, is that almost ANY weapon can be a sniper's tool.
Take this little story:
I was playing "Call of Duty 2: Big Red One" on my PS2 and was stuck on the last level. My sniper rifle was out of bullets and all I had on me was 2 grenades and an MP44 submachinegun. So what did I do? I flipped on the regular sight, aimed and took out that sonnovabitch in the tower raining hellfire with an MG42!