To elaborate on this a little: In old-school PC shooters the FOV was freely adjustable. People would be playing Quake with a FOV of up to 180°.
In the more recent time console shooters (and CoD especially) have massivey reduced the FOV (CoD has 65°, if I'm not mistaken), because it would give console-players a more natural feel when they sit far away from the screen.
http://img140.imageshack.us/img140/1692/modernwarfare2fovtuning.jpg is a comparison of the standard FOV in CoD and an increased one.
Now in old games the weapon would actually move towards the center when increasing the FOV. Oddly, it doesn't in CoD which makes it look a little weird.