Some models came with rifle sights and some came with ghost ring sights with a tritium " night sight " insert in the front sight.
12.
The gunner can also manually aim the guns, using either the optical system or an external backup ring sight provided on the outside of the turret.
13.
The rear sight consists of a metal tube welded onto the carrying handle in place of the original adjustable sight, creating a quasi-ghost ring sight.
14.
Ghost ring sights are commonly found on riot and combat shotguns and customized handguns, and they are also gaining ground as a backup sighting system on rifles.
15.
Bead sights are inferior in practical accuracy compared to rifle and ghost-ring sights, as they provide no rear sight to verify correct alignment with the front sight.
16.
Pom-pom directors I through III controlled the gun mounting through " follow the pointer " control and aimed at aircraft using eye shooting techniques through a simple ring sight.
17.
The sight was typical ring sight of the era, with an oval-shaped front sight with two consentric rings while the rear sight was a small peg surrounded by a protective ring.
18.
The ghost ring sights cost more, but they are generally considered better for defensive purposes, as they allow faster sighting under poor lighting conditions plus a longer sight radius for greater potential accuracy.
19.
The P90 was originally equipped with the Ring Sights HC-14-62 tritium module, and, in the HC-14-62, ambient light drawn in by an upward-facing collector.
20.
An auxiliary anti-aircraft ring sight is kept in the maintenance kit, and fitting on the barrel jacket to be used in conjunction with the folding antiaircraft rear peep sight attached to the rear sight base.
