The sight is defined as all mechanical, optical or optronic devices that allow an accurate aiming of the weapon. It is easy to understand their importance and we will present here the different aspects of this subject. Throughout this chapter we will use some notions that we deem necessary to explain beforehand:

• Sight picture: this is the image perceived by the shooter through the sights at the time of shooting.
• Tunnel vision: used in the field of shooting, this is a phenomenon that can be described by the disconnection of the user’s mind with events other than those occurring in the visual field of direct observation and in our particular case, in the visual shooting.
• Parallax: used in the field of shooting, it is a notion that refers to the difference in axis between the sights and, either the axis of the barrel, or the axis of the eye of the shooter. We will return to each of these cases later in this chapter.