Editing Tactical light (section)

==Weapon-mounted lights==
[[File:HK USP 45 surrounded by .45 caliber Hornady TAP (+P) jacketed hollow point rounds.jpg|thumb|A [[Heckler & Koch USP]] with a [[SureFire]] flashlight mounted below its barrel]]
Hand-held flashlights were introduced about 1900 with availability of [[dry cell]] batteries and [[incandescent light bulb]]s. Early bulbs were often too fragile to survive the acceleration of firearm recoil. A United States patent was issued in 1912 for a night sight for firearms demonstrated on a [[revolver]] with a bulb mounted in a [[shock absorber]] below the barrel and the grip modified to hold a battery and include a [[pressure switch]].<ref>Wood, J.B. "An Extraordinary Achievement" ''[[American Rifleman]]'' November 2013 pp.74&75</ref>

Weapon-mounted lights (sometimes called "weapon lights") offer hands-free use, leaving the operator free to use both hands to control the weapon. For rifles, two hands are needed to use the weapon. Most models have an on/off switch mounted on a short wire. The switch is then mounted somewhere on the gun within easy reach of the firer's fingers.  Weapon-mounted lights are most commonly seen on [[rifle]]s, [[shotgun]]s, and [[submachine gun]]s, but small tactical lights are becoming more common on [[handgun]]s as well.  These lights are often much more expensive than the handheld lights, since they must be sufficiently robust to withstand the recoil of the firearm, and the dedicated mounting hardware also adds to the price.  One downside of the weapon-mounted light is that it is always aimed parallel to the bore, so illuminating an object means that it is also targeted.  Because of this, weapon-mounted lights may not be appropriate under some [[rules of engagement]].

Weapon-mounted lights used to be specific to particular models of firearm, and to some extent that is still true; for example, [[SureFire]] makes dedicated lights that replace the forends of the [[Mossberg 500]] and [[Benelli M3]] shotguns, the [[Heckler & Koch MP5]] submachine gun, and the [[M4 carbine]]. On the other hand, many modern firearms are incorporating [[Rail integration system|rail integration systems]], allowing any appropriately-sized rail-compatible tactical light to be attached. Other mounting systems are simple clamps, designed to mount most cylindrical lights parallel to the barrel of most firearms. Using an infrared light in conjunction with night vision goggles can mitigate concern about revealing the user, so long as the target lacks night vision.  Also partially mitigating this risk associated with a visible light tactical light is the ability of the tactical light user to temporarily disrupt the night vision of the target.

=== Standard form factor and light bearing holsters ===
On most [[handgun holster]]s, the firearm is held in the holster via the [[trigger guard]], either via a locking mechanism or simply by the holster being a bit tight in that area and holds or clicks the firearm in place. On handguns with lights, however, it is often not possible to make a holster that retain the firearm by the trigger guard, and most such holsters therefore retain the firearm firmly via the light.<ref>[https://blog.werkz.com/?p=17 Six Things Your Light-Bearing Kydex Holster Will NOT Do – Werkz Blog]</ref> As such, ready-to-use light bearing holsters not only have to be made for a specific handgun model, but also a specific light,<ref name="policeandsecuritynews-2018">[https://policeandsecuritynews.com/2018/01/24/selecting/ Selecting a Light Bearing Holster | Police and Security News January February 2018]</ref> or at least for a light which shares the same or roughly the same form factor. One example of this is the SureFire 300 and 400 model series, which have retained the same form factor despite receiving numerous modifications over time. Pistol lights sharing the same form factor gives the possibility to upgrade lights to newer models and continue to use old holsters, as well as giving better aftermarket support for holsters. Some holsters can safely accommodate different types of lights.<ref name="policeandsecuritynews-2018"/>