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Surefire X400 Ultra Weapon Light Review

Doctor Dabbs examines Surefire's 1,000 Lumen X400 Ultra with its visible laser!

Surefire X400 Ultra Weapon Light Review

The Surefire X400 Ultra offers impressive capabilities in a rugged combat-proven chassis.

“In the beginning God created the heavens and the earth.” Thus begins the most extraordinary piece of literature in all of human history. The following verse reads, “And God said, ‘Let there be light,’ and there was light.” Light is what separates us from the darkness. Darkness is the default condition. Darkness is actually best defined as the absence of light. Most bad stuff happens in the dark. Only through the injection of light can the darkness be dispelled.

It has been said that most folks carry a gun because a cop is too heavy. The time we might actually need a weapon for real is not typically mid-morning after a good night’s sleep and a hearty breakfast. Most commonly you reach for that gun late at night when you’re out where the Wild Things Roam. Nowadays the possibility that you might require a defensive firearm in the face of urban unrest, or unexpected calamity, is frankly unprecedented. Under those circumstances the ready availability of a proper light can spell the difference between survival and tragedy. While I consider a good hand-held light something you should always have on you, what about a weapon mounted light? A good weapon light can be a great compliment to a good hand-held tactical light, and is highly recommended for many scenarios.

SureFire X400 Ultra

One to consider is the SureFire X400 Ultra. This compact combination white light illuminator and laser designator is 3.7 inches long and weighs a paltry 4.9 ounces fully loaded. The X400 Ultra produces a blistering 1,000 lumens of night-shredding white light through its rugged TIR (Total Internal Reflection) lens. The light will run for 1.25 hours on a pair of CR123A batteries while producing some 11,300 candela of light energy. The integral laser module can be had with either a 635nm red laser or a 515nm green version. These lasers put out the same amount of power, but the human eye detects green more starkly than it does red, so the green version seems to project with a bit more authority. The whole shebang is built into a robust hardcoat anodized aluminum body.

Surefire X400 Ultra Weapon Light Review
We live in some remarkably trying times. The very real probability of urban violence and social unrest makes a proper defensive firearm a necessity in many locales.

There is a manual of arms to a device like this. The pivoting tailcap switch is easy to use from either side both night and day. There is also a pivoting switch on the bottom of the unit that selects among the light, laser, or both. Naturally the whole rig is IPX4 water resistant. The IPX4 rating means the X400 Ultra is secure against vigorously splashing water from any direction. It is not submersible however. The X400 Ultra is both recoil-proof and rugged. Soldiers and cops the world over have beat the crap out of these things without any lasting deleterious effects. They have an excellent reputation.

The Host and Mounting

To put the X400 Ultra through its paces I mounted it up on a Kimber 1911 Custom TLE/RL II (TFS) sporting a SilencerCo Osprey sound suppressor. TLE stands for Tactical Law Enforcement. This Kimber pistol is well made with all the bells and whistles. The Osprey suppressor looks weird, in a manly sort of way, but is very effective.

Surefire X400 Ultra Weapon Light Review
The pivoting tailcap and function switch are intuitive and easy to use even in the dark.

Mounting the X400 Ultra requires nothing more than a cartridge case. Once secured in place pick a typical engagement range, shine the dot on a handy wall, and adjust the laser to meet the pistol sights using a small Allen wrench. Using this simple technique you can quickly zero the X400 Ultra without firing a shot. Of course, you should confirm on the range. The X400 Ultra is an impressive unit, but with an MSRP of $799 it is also undeniably expensive. You might be able to afford half a dozen of these things for all of your favorite tactical handguns, but I can’t. As a result, I swap my X400 Ultra around from one gun to another all the time. The X400 Ultra holds its zero easily between attachments to the same pistol. Tweaking the fall of the dot on a new gun only takes a moment per the description above.

Running and Gunning with the Surefire X400 Ultra

It takes a bit of practice to master the X400 Ultra, but it’s not like shooting is actual work. The switch is intuitive but learned. Practice with the selector switch in the dark until you can reliably choose among the light, laser, or both just by feel. The bilateral pivoting tailcap switch doesn’t care which hand you use. Keep in mind that shining a white light into the darkness under certain circumstances can make you a really big target. That’s why it’s nice to be able to switch functions on the fly. It’s important to know the strengths and weaknesses of employing a tactical light, especially when and how to use it. Training with it is also very important.

Surefire X400 Ultra Weapon Light Review
The Kimber, SilencerCo and SureFire light make an impressive combination which worked well together during testing.

In my experience 1,000 lumens is about as bright as it gets on a pistol-mounted light. Scurrying about my rural farm in the dark, the X400 Ultra will push clearly enough to identify the details of a target out to about fifty meters. The light is sufficiently bright to displace the darkness well past that. Having this light shined in your eyes in the dark is fairly disorienting.

Surefire X400 Ultra Weapon Light Review
At typical handgun ranges this gun/light/suppressor combination puts hits on targets, but practice is a must.

The laser dot is indeed easily acquired, particularly in a rush. However, for precision work you need to take into account the specific range. The height difference between the bore of the gun and the laser means, like the guns on a WW2 fighter plane, these two vectors will only converge precisely at a single point. The distance between the fall of the bullet and the laser dot at various ranges is entirely predictable, but something that also needs to be learned. Shining the dot on objects at various distances, and then comparing the spot to the lay of the sights, is the place to start.

Surefire X400 Ultra Weapon Light Review
A good weapon light should have enough output to dazzle your attacker and the beam should be wide enough to allow you to see their hands. (Benjamin La Londe photo)

With a little practice nothing is faster. The light carves through the darkest night, and the powerful green laser puts you on target as fast as your eyes can track. If the mission is to keep the monsters at bay while on the move, or around the hacienda during a crisis, the X400 Ultra leaves nothing to chance. You can run this light separated from the gun if you wish, but that’s not really what it’s designed for. Everything works just fine, but the switches just run more smoothly from the bottom of a pistol. The knurled screw mount takes a little intentionality to install and remove as well. However, in a pinch you could still use the X400 Ultra as a really powerful flashlight in places where you wouldn’t want to be waving a gun around.


Ours is a weird old world that gets daily weirder. Nowadays folks just don’t seem to be terribly nice to each other anymore. While the motivations driving that ignoble phenomenon would take an encyclopedia to explore, at least American industry offers us the tools we need to both survive, and thrive, in the face of such sordid stuff as urban riots and anarchy. Properly employed the SureFire X400 Ultra light/laser can be a combat multiplier and useful asset. However, this takes learning the unit and training with it. Should you have to move tactically through a dark building, or fight out of an automobile, you’d be hard-pressed to find a more optimized tool.

Surefire X400 Ultra

  • Weight: 4.9 ounces
  • Bezel Diameter: 1.125 inches
  • Output: 1,000 lumens/11,300 candela
  • Runtime: 1.25 hours
  • Batteries: CR123Ax2
  • Switching: Ambidextrous push/toggle
  • Laser Output: 5nW/515 nm
  • Laser Runtime: 24 hours
  • Laser Range: 213 meters
  • Price: $799

If you have any thoughts or comments on this article, we’d love to hear them. Email us at


About the Author:

Will is a mechanical engineer who flew UH1H, OH58A/C, CH47D and AH1S aircraft as an Army Aviator. He is airborne and scuba qualified and summited Mount McKinley, Alaska, six times…at the controls of an Army helicopter. After eight years in the Regular Army, Major Dabbs attended medical school. He works in his urgent care clinic, shares a business building precision rifles and sound suppressors, and has written for the gun press since 1989.

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