A laser sight is a device attached or integral to a
firearm
A firearm is any type of gun designed to be readily carried and used by an individual. The term is legally defined further in different countries (see Legal definitions).
The first firearms originated in 10th-century China, when bamboo tubes ...
to aid target acquisition. Unlike
optical
Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behaviour of visible, ultraviole ...
and
iron
Iron () is a chemical element with symbol Fe (from la, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, right in f ...
sights
A sight is an aiming device used to assist in visually aligning ranged weapons, surveying instruments or optical illumination equipments with the intended target. Sights can be a simple set or system of physical markers that have to be aligne ...
where the user looks through the device to aim at the target, laser sights project a beam onto the target, providing a visual reference point.
Although
lasers
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word "laser" is an acronym for "light amplification by stimulated emission of radiation". The fir ...
in the
visible part of the spectrum are most common, invisible
infrared
Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...
(IR) lasers may be used in conjunction with a
night vision device
A night-vision device (NVD), also known as a night optical/observation device (NOD), night-vision goggle (NVG), is an optoelectronic device that allows visualization of images in low levels of light, improving the user's night vision. The dev ...
.
As they are offset from the barrel, laser sights need to be
zeroed in, much like a conventional sight, so that the beam intercepts the
point of impact at a chosen distance. Devices may include one or both types of laser, with some models also incorporating a rangefinder,
flashlight
A flashlight ( US, Canada) or torch ( UK, Australia) is a portable hand-held electric lamp. Formerly, the light source typically was a miniature incandescent light bulb, but these have been displaced by light-emitting diodes (LEDs) since the ...
, or IR illuminator. Laser sights may be attached to the existing sighting mechanism, the
trigger guard
A trigger guard is a protective loop surrounding the trigger of a firearm designed to prevent unwanted contact with the trigger, which may cause an accidental discharge. Other devices that use a trigger-like actuator mechanism, such as inhalers, c ...
, via a
rail system
Rail transport (also known as train transport) is a means of transport that transfers passengers and goods on wheeled vehicles running on rails, which are incorporated in tracks. In contrast to road transport, where the vehicles run on a pre ...
, or can be integrated into replacement components such as the guide rod or
grip plates.
Some variants are also incorporated into other attachments such as
foregrips.
Laser sights are primarily used by military and law enforcement, although have some civilian use for hunting and self defense. They are also found on some
less-lethal
Non-lethal weapons, also called nonlethal weapons, less-lethal weapons, less-than-lethal weapons, non-deadly weapons, compliance weapons, or pain-inducing weapons are weapons intended to be less likely to kill a living target than conventional ...
weapons, such as
Taser
A taser is an electroshock weapon used to incapacitate people, allowing them to be approached and handled in an unresisting and thus safe manner. It is sold by Axon, formerly TASER International. It fires two small barbed darts intended to ...
electroshock weapons
Electroconvulsive therapy (ECT) is a psychiatric treatment where a generalized seizure (without muscular convulsions) is electrically induced to manage refractory mental disorders.Rudorfer, MV, Henry, ME, Sackeim, HA (2003)"Electroconvulsive the ...
.
Purpose
Benefits
Accuracy
The use of laser sights is associated with increased accuracy in general, increasing the probability of hitting the target especially in low light conditions.
[Will Houde-Walter "Violence reduction and assailant control with integral laser-sighted police pistols", Proc. SPIE 2934, Security Systems and Nonlethal Technologies for Law Enforcement, (29 January 1997); https://doi.org/10.1117/12.265415] The projected dot speeds up target acquisition, decreasing the time required for the shooter to aim and fire, as well as decreasing the time necessary for follow-up shots. Laser sights also aid in
point shooting
Point shooting, also known as target- or threat-focused shooting, intuitive shooting, instinctive shooting or subconscious tactical shooting, is a practical shooting method where the shooter points a ranged weapon (typically a revolver or semiau ...
, where the shooter relies on hand eye coordination rather than aiming with a traditional
sight
Visual perception is the ability to interpret the surrounding Biophysical environment, environment through photopic vision (daytime vision), color vision, scotopic vision (night vision), and mesopic vision (twilight vision), using light in the ...
. This is of particular use when the user does not have time or is unable to obtain a proper sight picture before firing; for example, the use of
ballistic shields or
gas masks
A gas mask is a mask used to protect the wearer from inhaling airborne pollutants and toxic gases. The mask forms a sealed cover over the nose and mouth, but may also cover the eyes and other vulnerable soft tissues of the face. Most gas mask ...
may obstruct access to the sights. Lasers also increase accuracy when shooting from an unconventional stance.
Training
Laser sights are also a useful training aid. They allow users to practice
dry-fire drills while being able to see the point of impact: this has significant
safety benefits. Training with laser sights has been shown to improve shooting skills faster, although both instructors and manufacturers recommended that users continue training without lasers to avoid becoming dependent on them.
Deescalation
By providing a visual indication of where the gun is aimed, laser sights add an extra factor of intimidation. Studies of law enforcement indicate that suspects faced with laser sights are significantly more likely to surrender, even if they themselves are armed.
Use with Night Vision Devices
IR (infrared) lasers can be used with night vision devices as the bulk of a head-mounted night vision device makes aiming with iron sights or a conventional optic difficult.
These lasers cannot be seen by the naked eye and are only visible when utilizing night vision devices. Some IR laser units, like the
AN/PEQ-2, utilize two separate lasers: a narrow "aiming" laser and a more diffuse "illuminator". The aiming laser is used to estimate point of impact while the illuminator is used to better visualize targets and the environment through the night vision device.
However, even with laser sights, shot groupings are still inferior to those achieved in daytime, and the degree of improvement is highly dependent on correct set up of the system.
Drawbacks
Long range accuracy
Where a laser beam travels in a straight line, the path of a bullet gradually deviates after it leaves the barrel due to external forces such as gravity, wind, and even the
rotation of the earth
Earth's rotation or Earth's spin is the rotation of planet Earth around its own axis, as well as changes in the orientation of the rotation axis in space. Earth rotates eastward, in prograde motion. As viewed from the northern polar star Pola ...
. This is a significant issue for long distance shooting; shorter range weapons such as handguns are less affected. Another related issue is that the beam widens over distance, meaning that instead of projecting a small dot, a much larger circle may be produced.
Visibility in bright light
Visibility of laser sights deteriorates in bright light. Green lasers are more effective in bright conditions, however they are more complex to produce so are often larger and more expensive than red lasers.
Aerial targets
Laser sights cannot be used for hunting flying game in the daylight as neither the beam nor dot are visible.
A further risk to aircraft is also an issue, as even civilian grade lasers are capable of hitting a plane from 2 miles away.
Batteries
Laser sights rely on batteries to work. As such, they require regular maintenance and may fail during use. Non-water resistant models also risk electrical damage through water ingress.
Added mass
As with all firearms attachments, laser sights add mass to the firearm. This is particularly significant for handguns as many holsters aren't designed to accommodate them.
Risk of eye damage
Lasers can easily cause damage to the eyes. Visible lasers are unlikely to cause permanent damage due to the blink reflex, however IR lasers do not trigger this and thus pose a significant risk.
Revealing position
The use of laser sights poses a risk in tactical scenarios as they may reveal the user's location, although this can be mitigated by only turning on the laser when needed.
An additional consideration for military and law enforcement is whether the enemy has night vision capabilities; if so IR lasers will be visible to them.
Difficulty zeroing
Laser sights are somewhat more difficult to zero than conventional sighting systems. IR lasers in particular can take in excess of an hour to properly zero, depending on the methods used.
Boresights
Laser boresights differ from laser sights in that they are not intended, or capable, of being used at the same time as the firearm; instead, they are intended to aid in
zeroing
In measurement technology and metrology, calibration is the comparison of measurement values delivered by a device under test with those of a calibration standard of known accuracy. Such a standard could be another measurement device of know ...
the firearm. A boresight is a laser in the shape of a
cartridge
Cartridge may refer to:
Objects
* Cartridge (firearms), a type of modern ammunition
* ROM cartridge, a removable component in an electronic device
* Cartridge (respirator), a type of filter used in respirators
Other uses
* Cartridge (surname), a ...
. The user
chambers
Chambers may refer to:
Places
Canada:
*Chambers Township, Ontario
United States:
*Chambers County, Alabama
* Chambers, Arizona, an unincorporated community in Apache County
* Chambers, Nebraska
* Chambers, West Virginia
* Chambers Township, Hol ...
a boresight of the appropriate
calibre
In guns, particularly firearms, caliber (or calibre; sometimes abbreviated as "cal") is the specified nominal internal diameter of the gun barrel bore – regardless of how or where the bore is measured and whether the finished bore match ...
which projects a laser beam directly down the barrel, providing a visual indicator of the point of impact at a given range. The user then adjusts the sights until they align with the dot. Boresighting suffers from the same weakness as laser sights in that while the beam is straight, the path of the bullet curves; as such it is not a substitute for traditional zeroing, rather they serve to speed up the process.
Law
Restrictions on laser sights vary by jurisdiction. Another consideration is the legality of the laser itself: the power output of military and law enforcement issue devices often exceeds that permitted for civilian use.
U.S.
In the U.S. laser sights are mostly legal for self-defense purposes, however their use for hunting is more strictly regulated.
UK
UK firearms legislation does not mention accessories such as laser sights. There are no restrictions on using laser sights on rifles at a range.
Users
U.S. police
In a 2019 survey of US police officers, less than 13% used laser sights on duty, with only 32% saying that their agency permitted their use.
References
{{Firearms
Firearm sights
Firearms
Firearm terminology
Firearm components
Military technology
Military electronics
Military equipment
Military equipment post-1945
Laser aiming modules