Iron Sights

It's a system of shaped alignment markers (usually made of metal strips or blades ) used as a sighting device on firearms & Cross bow, to assist the shooter in aiming & shooting accurately. Iron sight is a system of 2 component sights

- Rear sight - made of thin metal blades. It's usually notch shaped or a circular ring. Mounted close to the eye which allows easy visual pick up of the notch

- Front sight - usually made of slightly thicker metal pieces or metal blades. Usually comes in bead, post, ramp shaped.its usually mounted on barrel or stacking to muzzle is at some distance from eye aligned in the center of rear sight ring or notch

Classifications

There are 2 types of iron sights --

 - Open Sights - in this sight the rear sight is notch shaped (usually U or V notch) and front sight is square post or bead on the post as sight which is positioned both horizontally and vertically in the center of rear sight. The front size is at significant distance from eye

 - Aperture Sight - In this sight the rear sight is usually a thin circular ring which is referred as ghost ring bcs it's nearly invisible due to it's nearly invisible when shooter aims through it. Front Sight is either post or ramp shaped. In this system the front sight can be positioned in center of rear sight ring or can be positioned slightly sided from center

Types according adjusting :-

 - Fixed iron sight - These sights are very simple in design,fixed and non adjustable or less adjustable mostly used in old guns or hunting, or sporting rifles

 - Adjustable Iron sights - These sights are adjustable according conditions or distance of target. Usually the rear iron sights are adjustable while front sight is fixed

Source - Wikipedia
info gathered by - Best - The Silent One from Defence matrix discord