FN P90: Versatile Optics

by Al Paulson

The optical sight is made from a solid piece of glass so there's no risk of nitrogen leaking and subsequent fogging in the field. It has two complementary reticle patterns for differing lighting conditions.

A day reticle, which is projected into the sight from the front, features a circular reticle which provides very rapid target acquisition throughout the effective range of the weapon. The reticle has several markings which complement each other. A very large circular reticle provides fast target acquisition at panic-close range, while a much smaller circle is optimized for target acquisition at 100 meters but works very well at closer ranges. A tiny dot inside the smallest circle can be used for maximum finesse; this dot lies 3.7 inches (94 mm) above the center of the bore.

A low-light reticle, which is illuminated by a replaceable tritium cell, is projected into the optical sight from the rear. It is normally invisible in bright daylight conditions unless the sight is shaded by the brim of a large hat. A horizontal reticle runs across the center of the field from one side to the other, and a vertical reticle runs from the bottom of the field to the small circle. These lines form three legs of a traditional crosshair reticle, which can be quite useful inside dark buildings or during low-light operations outside. In those relatively rare lighting conditions where both the day and night reticles are visible, the sight picture is still uncluttered enough to provide rapid target acquisition.

first published in the November 1998 edition of Guns and Weapons for Law Enforcement