Holosun IRIS-GR4 Review: One Box for Laser, IR and White Light

The Holosun IRIS-GR4 is the green-laser version of the IRIS 4, a quad-function aiming and illumination device for a rifle's top rail. One 7075-T6 aluminum housing holds a 520nm Class 3R green laser, a Class 1 IR aiming laser, a 60mW VCSEL IR illuminator and a 1,000 lumen white light. The IRIS-RD4 is the same unit with a red visible laser. If you are new to night vision lasers, our IR illuminator guide explains what an illuminator does that an aiming laser does not.

The visible and IR lasers are co-aligned at the factory, so you zero the green laser in daylight and the IR laser lands on the same point under night vision. A slider on top of the housing adjusts the IR illuminator from a wide flood to a tight spot. Power comes from two CR123A batteries or one 18650; ours shipped with two CR123As in the case.

The IRIS-GR4 held zero through more than 1,000 rounds on our Knight's Armament SR-15, across two 2-gun matches and several range sessions. We never had to touch the windage or elevation after the first zero.

One of those matches ran at night, and that is where the IRIS earned its spot on the rifle. We used every function on it. The white light let us see and identify targets out to about 50 meters, a realistic distance for a 2-gun rifle stage. The green laser was bright enough to aim with at night, and the IR laser and illuminator worked well under night vision.

We picked the IRIS-GR4 for this rifle because of weight. The SR-15 was already a little front-heavy, and a separate IR laser and weapon light would have made it worse. One 8.5 oz box on the top rail fixed that while keeping every function we wanted.

The IRIS-GR4's weak spot is its controls, starting with a second body button that is hard to find and hard to press in the dark. There are two buttons on top of the housing. The dimpled main fire button was easy to find by feel at the night match. The hex-shaped button next to it was not, and we fumbled for it more than once. Neither button ever failed to work. It is a feel problem, not a reliability one.

The dimpled main fire button fires whatever the rear selector is set to. The hex button turns on the white light, and the visible laser comes on with it. The rear selector has an off position, low and high visible laser positions, and six IR positions that run the IR aiming laser, the illuminator, or both, each at low or high power.

The included pad gets the layout backwards. Its easiest button to find is a small raised round button that fires only the green laser, a function most shooters rarely need. The two buttons you actually use, the IR fire and the white light, are large, flush and textured almost the same, so telling them apart in the dark takes practice. Under night vision, a missed press on the raised button puts a visible laser downrange instead of your IR.

The pad is a three-button unit on a dual-lead Crane plug. Holosun calls the round button the VIS override: it fires the green laser even while the rear selector is on an IR mode, at the selector's low or high power, so a shooter under night vision can show a target to someone who is not wearing it. The middle button does the same job as the main fire button on the body, and the end button turns on the white light and green laser together. We ran the body buttons instead.

The IRIS-GR4 matched our Wilcox RAID Xe for IR at carbine distances, for $999.99 against about $3,823 for our other night setup. That setup is an LMT with a Wilcox RAID Xe, a Cloud Defensive REIN 3.0 and a Unity AXON switch. Under night vision we saw no meaningful difference between the two IR illuminators at the distances we shoot. The RAID Xe does more on paper: a programmable pad, a fixed 40-degree room illuminator and stepped power settings.

White light is where the REIN wins. It is rated at 1,250 lumens and 100,000 candela, four times the IRIS's 25,000 candela, so it throws much farther. The IRIS light was still very usable at 50 meters. On weight, the IRIS-GR4 is heavier than a REIN alone, but the RAID Xe and REIN together come to about 13.8 oz before the light mount and the switch, against 8.5 oz for the IRIS.

Buy the IRIS-GR4 if you want IR and a white light on a gun that is short on rail space or cannot take much weight out front. That covers subguns, pistol caliber carbines, short SBRs and rifles that are already nose-heavy. You get a VCSEL illuminator, co-aligned lasers and a real weapon light on one rail slot and one zero. Our AR-15 night vision setup guide covers optic heights and the rest of the rifle around it, and you can price the whole rifle in the rifle builder.

Skip it if you already own a weapon light you like; the IRIS 3 gives you the same lasers and illuminator without the light. Skip it too if you need the longest possible white light throw, because a dedicated 100,000 candela light outreaches it. Our best Holosun optics guide compares the IRIS 3 and IRIS 4 side by side.