Nuclear-Powered Sighting Systems

Tritium And XS Luminous Night Sights

By Will Dabbs MD

XS Sights is a family-owned American gun sight company tracing its origins back to 1996. Melding the state of the art in modern technology with practical feedback from some of the biggest names in gunfighting, XS set out to craft the best low-light gun sights in the world. They now offer a wide selection of superb luminous gun sights for a bewildering array of firearms.

We never seem to train much in the dark, yet this is where most defensive engagements will inevitably occur. Criminals are typically opportunistic bottom-feeders, and they tend to operate at times and places insulating them from retribution — and the cops. Those of us who choose to assume personal responsibility for the safety of our families should equip and train accordingly.

Night ranges in the military were always exciting. Back in the days before ubiquitous night vision devices, night firing iterations typically involved taping chem lights to targets downrange and blasting away with tracers until we had burned through our ammunition allotment. The standard iron sights on an M16 are literally invisible after dark and walking tracers onto a target was a crude solution at best. The resulting exercises were unabashedly fun but fairly worthless.


XS Sights offers superb flip-up luminescent backup iron sights for all tactical long guns.
These sights glow nicely in the dark and snap out of the way when not in use.


Here (red arrows) you can see the rear/front iron sight set-up and how it’s off-set.
Out of the way but right at hand should your optics go down.

A Spot Of Science

Non-luminous gun sights are useless after dark. The best way to address this problem is to perch a bit of genuine nuclear material atop your weapon. Tritium is a radioactive isotope of hydrogen, the nucleus of which contains one proton and two neutrons. This remarkable material is produced within nuclear reactors by the neutron activation of Lithium-6. It’s also an uncommon product of the nuclear fission of Uranium-235 and Plutonium-239, though it’s obviously a bit tougher to recover and refine after a nuclear explosion. Among its many applications, tritium is employed in atomic bomb design to increase the efficiency of nuclear weapons. Its more sinister attributes notwithstanding, in its native state tritium is a low-energy beta emitter. As beta particles do not penetrate human skin, so long as you don’t eat it, tritium is harmless to humans.

The most common use for tritium is self-powered lighting, such as watch faces and weapon sights. For these applications the tritium is enclosed within a glass vial lined with a phosphorescent coating. The tritium activates the coating, and your eyes perceive the glow. The worldwide appetite for tritium is on the order of 400 grams per year, and refined usable tritium costs about $30,000 per gram. That’s about 689 times more expensive than gold, so now you know why tritium sights can be spendy at times.

Tritium is an unstable radioactive isotope with a half-life of 12.32 years. For a variety of technical reasons, however, tritium inserts lose about half their practical brightness in about three years. I have typically gotten 8 to 10 years out of mine, though they obviously still function as conventional iron sights regardless. I used the tritium inserts in my aviator’s watch as an effective flashlight while under night vision goggles back when I was a soldier.


Angled backup iron sights from XS Sights include luminous tritium inserts (front and rear sights)
and are mounted so a quick snap of the gun around its axis brings the sights to bear. In this
configuration the iron sights are both out of the way and always available.


Glowing tritium night sights from XS Sights are available for all common tactical handguns and include most
everything you need to mount them yourself at home painlessly. A set of luminous replace-ment steel night
sights (left) is a marked improvement over the standard factory polymer GLOCK sights (right). Easier to acquire
and functionally indestructible, these sights really expand the utility of an already-superb handgun.


XS tritium-powered gun sights do not require batteries and are subsequently just as compact as conventional iron sights. XS offers tritium night sights for just about any commonly encountered handgun, rifle or shotgun. They offer handgun sights which are standard height as well as raised versions for use alongside sound suppressors. Whether your application be pocket pistols, full-sized combat handguns, modern sporting rifles, tactical shotguns or hunting guns, XS likely has a sighting rig to enhance it.

For tactical rifle and carbine platforms they offer flip-up backup iron sights as well as angled offset sights which come into play with a quick rotation of the rifle around its bore axis. This exercise is easier to do than to describe and offers instant access to unbreakable illuminated iron sights in the event of primary sight failure.

I occasionally pack a slim GLOCK 43 in an ankle or belt holster when the threat level is low and my desire for comfort outweighs my concern for serious security. While GLOCK makes an undeniably fine handgun, their polymer sights are yesterday’s news. A set of no-snag tritium night sights from XS optimizes the little gun for the places where it’s most likely to be employed. The front sight dot is markedly larger and subsequently easier to acquire than the factory version. The angled rear sight incorporates a single luminescent aiming post. The subsequent rig is a mighty improvement over the originals.

Most everything required to swap out the sights is included in the package, including a non-marring punch and thread-locking compound. A sight-pushing tool is not required or recommended. You supply the hammer, and a vice is handy but not technically necessary. Follow the instructions or take in their excellent YouTube videos for the details. Swapping out the sights is well within the capabilities of anyone with even a modicum of mechanical ability.


The XS Sights pistol sights on Will’s GLOCK 43 consist of a luminous rear post
and an oversized front dot, both of which glow brightly in hard dark.

Practical Utility

The difference between factory sights and a set of tritium-powered night sights is either aiming your weapon — or shooting blindly. I found a spot with a safe backdrop and shot at a target illuminated softly with a chem light, both with XS tritium-powered night sights and without. In practice the glowing XS night sights naturally capture your gaze and I was pleasantly surprised I could print proper groups with these sights, even in dim light conditions.

We will seldom be called upon to use our defensive weapons in broad daylight after a hearty breakfast and a refreshing shower. Any real-world defensive engagement will be fast and terrifying. When this happens, having a set of sights instinctively grabbing your eye, even in pitch darkness, can spell the difference between success and death.

In the grand scheme these aftermarket sights are not expensive and they are more robust than your host weapon. Perching a bit of radioactive material atop your favorite tactical firearm will offer a nice edge when the threat lurks in the dark.

For more info:, Ph: (888) 744-4880

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