Primary Arms GLx 1x microprism review

Prism optics have come a long way in the last 10 years. Primary Arms has been one of the leaders in prism designs. Their Microprisms were one of the first, if not the first, to be able to be used with magnifiers and back up iron sights. Primary Arms recently came out with their newest Microprism in their GLx line. This is the GLx 1x MicroPrism with the ACSS Cyclops reticle. The GLx microprism improves on the Primary Arms SLx line of microprisms, which were a fantastic product by themselves.

I have become a huge fan of 1x prism optics, the new GLx 1x microprism just enhances my fandom. The GLx 1x microprism has fantastic glass clarity and a decent size objective lens. It doesn’t weigh much. Primary Arms includes a bunch of different mounting options. They use readily available batteries that now load from the top. It also now uses push button controls as well as continuing to use their “Autolive” to turn the reticle on and off.

Part of what makes the GLx 1x microprism nice, is the glass clarity. Looking through it, it is super clear. As is the reticle, at least after you adjust the diopter to your eye. I am not sure if the clarity is better because of the larger objective lens, or better glass. Both of which are better than Primary Arms’ SLx line of microprisms. Either way you get a super clear optic. Since this GLx is a prism, you will have eye relief. Primary Arms states an eye relief of 4.4 inches. But do not be fooled by this. These new microprisms can be used from about 1 inch out to a foot or more. I noticed that the new GLx seems to even have more eye relief than the SLx line, and it was amazing. Another thing people worry about with prism sights over red dots, is the viewing angle. For me, the reticle could still be seen at almost any angle, as long as you could see through the prism, you can make out a full reticle picture. When Primary Arms sent me the GLx prism, they also sent a “kill flash”, or anti-reflection device, with it. It just screws over the objective lens. It helps to block glare, both from looking through it, or looking at it. The kill flash is a nice little add-on if you like these things, or need them.

Primary Arms gave the GLx 1x microprism their ACSS Cyclops gen II reticle. The ACSS (Advanced Combined Sighting System) Cyclops is a horseshoe style etched reticle with a chevron, think triangle, in the middle. The round horseshoe part gives extremely fast target acquisition, especially for close up targets. It is also about the size of a 00 buck pattern at 25 yds. The chevron then takes over for precise aiming. You can also use the chevron like you would a red dot, if up close. The top point of the chevron is where you would zero your rifle. This point is also where you get pretty precise aiming by just putting the point on the target. The zero depends on what barrel length and caliber you are using (see picture). With a 16” 5.56 barrel, it would be 100 yds. The inner point of the chevron is now a bullet drop compensator. So with the same 16” barrel, this would be for 300 yds. Then the bottom part of the chevron would be 400 yds. The BDC is just a close estimation, since it also depends on ammunition type and the height at which the GLx is mounted. There is also range estimation built into the GLx microprism. It uses a 5’10” tall or 18” wide object for range estimation. When sighting in, the GLx uses 0.5 MOA clicks for both the windage and elevation adjustments. The clicks are very positive. The adjusting dial is recessed into the GLx’s housing so that the adjustments won’t be hit and knocked out of zero. It also makes for a smoother look. The 0.5 MOA adjustments are a great improvement over the SLx line that has 1 MOA adjustments.

Going along with the ACSS Cyclops reticle, the GLx also uses Primary Arms’ “Autolive”. The Autolive function turns the reticle off when not in use and then back on when the optic gets moved. It takes a miniscule amount of movement to turn it on. Of course it brings the reticle back on to the last brightness setting the optic was at. The Autolive gives the illumination part of the reticle about 10,000 hours of battery life, on a useful medium brightness setting. Because this is a prism optic, the reticle is also etched onto the glass. So even if your battery does die, you can still use the optic.

Part of why I like these new microprisms so much is that they can be used with a magnifier. Prism optics of the past used to not work with magnifiers. So now, if you were to want more magnification, you can just put a 3x or 5x magnifier behind the prism. Also, if you are old school, the GLx 1x prism will work with backup iron sights. Just another reason to like these new microprisms.

The GLx 1x is called a microprism because it is not very large, imagine that. It is about the size of your typical rifle red dot. In fact, it is only 2.6 inches long and 1.8 inches wide at its widest point. It is fairly lightweight at 9.1 ounces, which is only 1.5 ounces more than its little brother the SLx. In the box with the GLx are different riser mounts. You can configure them for 8 different mounting height options, something you do not get with other prism sights on the market. If one of those 8 heights does not suit your needs, the GLx uses a standard mini-ACOG mounting profile.

Reticle brightness is controlled by up/down buttons on the left side. The GLx 1x microprism has 13 available brightness settings. The lowest 3 are night vision compatible with everything else going up to daylight bright in sunlight. The daylight bright is not as bright as Primary Arms’ NOVA reticle, or your typical red dot, but it is still bright enough to use. When you push the up button continually, and the brightness reaches max brightness, the reticle will flash. A pretty nice addition to easily see if you are maxed out on brightness. I do not have night vision, so I do not know if it does it at the minimum brightness level. One CR2032 battery is used for the illumination and is housed on top of the microprism. If you do not want to use the Autolive function, you can hold both buttons down to turn the optic completely off. Just push either up or down to bring it back online.

I installed the GLx 1x microprism on a 300 blackout build. I am using both subsonic and supersonic rounds in this thing, so a 1x prism is the perfect sight option for me on this AR pistol. The GLx performed fantastic. I was able to ring steel at 200 yards with both subsonic and supersonic rounds. I just had to hold at the bottom of the chevron for the subs. The clear glass made seeing the targets easy. Since the GLx has an etched reticle, it plays nice with my astigmatism. I even ran some bill drills up close by just putting the horseshoe on the target, kind of like a circle-dot red dot. I am faster with just a red dot, but the microprism is not far behind in the speed category.

Going into this review, I already knew I liked 1x prism sights. The Primary Arms GLx 1x Microprism did not disappoint. The ACSS reticle gives the GLx something over just a dot and doughnut reticle. Eye relief is phenomenal. It has good light transmission. Let us not forget the Autolive function. Plus, all those mounting height options. The Primary Arms GLx 1x Microprism is definitely something you will want to check out.

Firearms Insider Reviews - Key Points

Claim to Fame:

Quality, streamlined 1x microprism optic

Target Market:

Anyone wanting a prism optic or those that have trouble with red dots

Features, Benefits, and Specifications of this product:

Battery Life: 10,001 - 25,000 Hours, 15,000 at setting “5”
Battery: CR2032
Click Value: 1/2 MOA
Exit Pupil Diameter: 18.8mm
Eye Relief: 4.4 in
Field View at 100yds: 74.8 ft.
Illuminated reticle
Length: 2.6 in.
Magnification: 1X
Mount Compatibility: Primary Arms MicroPrism, Trijicon Mini-ACOG
8 mounting height options included
Night Vision Compatible: Yes
Objective Diameter: 20.5mm
ACSS CYCLOPS Red Reticle
Total Windage and Elevation Adjustment: 50 MOA
Weight: 9.1 oz.

What other aesthetic options or finishes are available?

GLx with Green Cyclops reticle

What others are saying?:

4 out of 5 stars from Stephen at Primaryarms.com

As expected

I expected these to top their predecessors. I didn't expect them to be a great deal better. They are much better! The larger diameter, the lack of illumination knob, and the clear glass make these a home run and more than adequate red dot replacer. Same reticle as the previous version which is great. I have a red and green model and found the illumination to be good. Crisp reticle and clear glass. Thanks PA.