Even though such setting (close-up look) is rarely seen on screen, it is a challenge for a graphic. We should not only pay attention to the proper setting but also to the design and functionality of the scopes.
In reality there are a few types of scopes depending on their work and usage, etc.
In video games the situation is much simpler. It doesn’t matter whether weapon is equipped with a scope, iron sights or optical sight – „aiming” is only about pressing the right button and the weapon’s object changes its position on the screen.
The biggest discrepancies in the aiming rule occurs in the iron sighting. In reality:
to aim, one needs to coordinate all devices (usually the fore sight and the rear sight or the sight vane) and the target in one line. source
In video games, however, it is possible to ignore the fore sight/ sight vane and aim only with the rear sight. Games’ creators take that step in order to improve functionality. As then the rear sight or sight vane does not cover the battle field.
It shows that while aiming in a FPS game weapon should show clearly which point on the screen is responsible for hitting, so which place we will shoot at. Determining this point and the player’s comfort is much more important than correct (realistic) copy of the operating principles of the whole system.