A WEAPONLIGHT'S PURPOSE

A properly designed weapon-mounted light serves two primary purposes:

• It provides sufficient illumination to locate and identify potential threats in low-light situations.
• It provides sufficient illumination to temporarily overwhelm an aggressor's dark-adapted vision without significantly degrading that of the user.

There are other features to consider in selecting a WeaponLight, but if it can't accomplish these two purposes then you don't want it.

RECOMMENDED MINIMUM OUTPUT

The minimum amount of light required to achieve objective number one (above) depends on the search/engagement parameters: close- or long-distance search perimeter; indoor or outdoor environment; reflectivity of any surrounding surfaces; use of magnifying optics.

Objective number two is more clear-cut. To be able to sufficiently degrade the dark-adapted vision of an opponent 10 yards or less from your WeaponLight, SureFire recommends a minimum output of 50 lumens of non-diffused light produced by an LED light source. Non-diffused means that the greatest portion of light output is focused forward in a comparatively narrow cone, as is the case with all SureFire WeaponLights, all of which use either a precision reflector or a precision Total Internal Reflection (TIR) lens.

SureFire no longer recommends using weapon-mounted lights that use an incandescent emitter; therefore we no longer recommend a minimum output for such devices. More on this subject below.

IS MORE LIGHT BETTER?

Generally speaking, more light is always preferable. But there are other factors to consider relative to your specific mission requirements:

• In close-quarter situations an excessively bright light can bounce off walls, windows, mirrors, and other reflective surfaces and into your eyes, dangerously degrading your own night-adapted vision.
• Higher light output usually requires more power, meaning more batteries, which can add weight to your WeaponLight. More weight means a heavier, less maneuverable weapon. The more your gear weighs, the more energy you expend transporting it, which can add up in combat conditions and training exercises.
• High-output WeaponLights typically don't run as long as lower-output lights powered by the same number of batteries. A shorter runtime means you'll consume more batteries and may necessitate carrying more spare batteries on missions.

For longer-range applications where you need a lot of output and extended reach, a high-output WeaponLight is, of course, the best choice. But for closer-range applications, a lower-output WeaponLight that meets SureFire's recommended minimum output may be preferable.

BEAM CONFIGURATION IS CRUCIAL

Any illumination tool is limited to a certain maximum total amount of light output, which is measured in lumens. How this light is distributed in the beam that leaves the tool — the beam configuration, which is controlled by the tool’s focusing element and/or any diffusing element — determines the tool’s suitability for a given purpose. Beam configuration for illumination tools that produce cone-like beams (as opposed to those which produce area illumination, such as camping lanterns) can be divided into three basic types:

Flood beams, in which the light is evenly distributed in the output cone (see Figure 1). A flood beam is arguably optimum for strictly close-quarter battle (CQB) applications, where you must not only be aware of what is immediately in front of you but also of what is around you – to the sides, above, and even below in certain situations — and therefore having sufficient light for your peripheral vision is extremely important. Also, a true flood beam has no “hot” spot that naturally attracts the user’s attention and whose reflection off walls or nearby objects risks producing a “blank spot” afterimage in the user’s dark-adapted vision. SureFire does not produce WeaponLights with true flood beams because their application would be limited to strictly CQB applications. A modified general-purpose beam (see below) is more useful because it can be given more "reach", extending its application beyond CQB. However, a flood beam can be created by attaching a SureFire diffuser to the WeaponLight.

General-purpose beams, in which a significant percentage of the light is allocated to a brighter central cone and the rest is distributed more or less evenly in the surrounding cone (see Figure 2). If done properly — with the bright central area not too bright and not too sharply defined, and with no rings or dark spots, which has been a hallmark of SureFire lights from the beginning — this beam configuration is optimum for close- to mid-range work. The bright central area has much more reach than the flood light, yet there is sufficient light for the user’s peripheral vision, thus enhancing situational awareness.

Spot, or spotlight, beams, in which almost all the light is concentrated in a very narrow central cone, with only incidental “stray” light in the surrounding cone (see Figure 3).This beam configuration is optimized for maximum reach but is not suited to closer work because (a) reflection of this concentrated beam off close surfaces is likely to degrade or “burn out” the user’s dark-adapted vision, leaving a spot afterimage; (2) there is insufficient light available for the user’s peripheral vision; and (3) related to but not exactly the same as the previous item, the user’s eyes will almost instantly adapt to the high light level in the bright narrow cone, which means that anything outside of the bright area will be essentially invisible.

The beams on SureFire's medium-output X-Series WeaponLights, our Shotgun Forend WeaponLights, our RAID™ WeaponLight, and our Scout Light^® WeaponLights are all general-purpose beams that lean toward closer-range work due to their particular beam configuration and lower output compared to some of our other lights. While the comparatively lower output lessens the risk of degrading the user’s dark-adapted vision, these are still powerful lights with a central cone that provides surprisingly good reach.

Our mid-range WeaponLights (such as our X300 Ultra, our M900L, our M500L and others also feature general-purpose beams, but these have a higher light output and more concentrated central cones, giving significantly more “reach” while still providing good peripheral light for situational awareness.

And our longer-range WeaponLights (such as our M900LT, our M500LT, and our HellFighter^® heavy gun WeaponLights combine the highest outputs available with reflectors or lenses designed to maximize the beam's reach.

THE RIGHT EMITTER

All current SureFire WeaponLights, with the exception of our HellFighter^®WeaponLights, utilize light emitting diodes (LEDs) as emitters. At this point in the technological evolution of illumination tools there is no reason to use a weapon-mounted light with an incandescent emitter, and many powerful reasons not to use one. The fact is, all incandescent lamps feature a tungsten filament that will eventually break, either from excessive recoil or impact shock or from unavoidable and normal filament erosion. This was true for SureFire’s original WeaponLights even though they utilized high-quality filaments shock-isolation systems. Also, an incandescent lamp is much less efficient at producing visible light than an LED, which means it depletes its battery power quicker than a comparable-output LED.

In contrast, solid-state LEDs have no filament to burn out or break, so they're virtually immune to the effects of recoil and never need to be replaced. As mentioned, they're also much more efficient than incandescent lamps, so an LED will run longer on a set of batteries than a comparable-output incandescent lamp.

Previously the only downside to white-light LEDs was that they produced only negligible amounts of infrared radiation; therefore they could not be fitted with an infrared filter and then used with night vision devices (NVDs). However, in 2009 SureFire introduced its V-Series WeaponLights, which use a multi-spectrum LED that encapsulates both white light and infrared radiation in a single compact package capable of changing spectrum with the twist of a bezel, with no need for an IR filter.

SWITCH SELECTION

In high-stress situations, when there's no time to think, just to react, operating your WeaponLight needs to be second nature. An ergonomic, intuitive, fail-safe switch on your light is critical. You need one that turns on when you need it, off when you don't, and won't accidentally activate and give you away. A switch that does all of these things, and allows you to operate your light without sacrificing your shooting grip, is about as good as it gets. Every SureFire WeaponLight gives you all of the above.

MOUNTING CONSIDERATIONS

How your WeaponLight mounts to the weapon is another important consideration. SureFire WeaponLights attach to your weapon in one of three ways. The mounting option available depends on the WeaponLight selected and the make and model of your firearm.

BATTERIES

A high-performance WeaponLight demands an equally high-performance power source. SureFire WeaponLights (except the HellFighter®) are powered by SureFire 123A lithium batteries. These 3-volt high-energy cells are powerful, affordable, disposable, and offer significant advantages over alkaline batteries, including: