The in-game FOV slider is being used be numerous players to gain the kind of zoom that should only be available with a scope.

If you watch almost any stream, or youtube video, it will not take long for you to see someone go to the in-game options and put the FOV temporarily at the minimum when scouting an area or taking a shot with a gun that has no scope. This results in a overly zoomed in view that should simply not be available in-game.

The FOV needs to be set from the main menu, and the in-game option needs removing entirely, an example screen could show you how this looks so that you can get it right. FOV should be set to what works for you, and you should have to stick with that whilst playing. It is abusing an unintended feature to have binocular eyes whilst scouting, and fish eyes whilst running around.

As a final note, the ranging and mildots need to work perfectly with whatever FOV the player wants to use.