Many rifle shooters use optical sights for long range shots, or some sort of reflex sight for closer engagements. The concealed carry weapon is a sidearm and pretty much restricted to iron sights or laser devices. Ranges for handgun engagements are fairly short. Sighting radius and other concerns seldom factor into handgun employment in self defense scenarios. Sighting radius is the distance from the front to rear sight. The longer the distance between iron sights the more accurate the shot placement. A one eighth sighting error across 4 inches will throw the shot off more creating a 1.8 degree error while than a eighth inch error angle error across 16 inches will be related to 0.45 degrees of error or about than a 27 minute arc of accuracy. In the close ranges involved in handgun defense shooting these errors are not that significant. Shot placement to center mass, i.e. the sternum area will suffice.
Shot Placement Aim
Defensive handguns usually exhibit accuracy of 1 to 4 inch spread at 25 yards or 4 to 16 minutes of arc. However, most gun fights are fought from touching distance to the statistically determined range of 7 yards or about 20-25 feet. At typical combat ranges deviation in shot placement the point of aim is from about 1/2 to 1.25 inches. That is plenty accurate enough to get the job done.
Shooting in Low Light Conditions
Low light conditions are problematic. Black front sights are hard to see, spreading shot placement. White sight paint helps, particularly if it is the rear sight which usually consists of two white dots on the sight blade on either side of the notch. Line up the white dots, until level and the front sight is evenly centered and accurate combat accuracy is achieved.
Tritium Gun Sights
Tritium is a low energy radioactive glow in the dark substance, and is common in low light sights. Tritium does deteriorate, as tritium is a Hydrogen isotope with a half-life of about 12.3 years. About 5.5 percent of the tritium decays to Helium-3 every year, dimming in the process. Useful life is between 4-8 years depending on content and personal preference. It is a gas and contained in miniature vile placed in the sight.
Fiber Optic Gun Sights
Fiber optic sights gather existing light and concentrate it to produce a colored circle, usually green or red for sighting purposes. Like tritium sights these provide a high contrast sight picture for low light engagement. Many consider the fiber optic sight types to be somewhat fragile prone to damage, in practice they’re only slightly more susceptible to damage than straight iron sights.
Laser Gun Sights
Some prefer laser sights. They project a dot, usually red onto the target and properly sighted a bullet with shoot to the point of light or within a two inch circle depending on gun, ammunition and range. Laser sights do have a down side. They are electronic devices requiring a power source, meaning batteries. Batteries are subject to failure and the sights themselves add bulk and projection outside of the firearm requiring special holsters.
Optical sights are too bulky, don’t work well for target acquisition at combat ranges and under combat conditions. They are not practical or recommended for daily concealed carry.