Primary Arms GLx 2X Prism sight acss gemini
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I know pistol caliber carbines are most often paired with red dots, but I’ve long advocated minimally magnified optics that get you closer to the target. I love the red dot, but the Primary Arms GLx 2X prism fits right in as my ideal PCC optic. The GLx 2X comes outfitted with the ACSS Gemini 9mm reticle, and it allows you to reach out and touch targets with 9mm projectiles with precision beyond normal ranges. 

PCCs aren’t for everyone, but as a kid who grew up as an M1 Carbine fan, I can’t help but love these guns. While 50 to 100 yards doesn’t seem to be precision territory, there’s no reason to completely abandon the idea of combining accurate and precise shots.

A minimally magnified optic allows you to easily hit targets quickly at close ranges and also stretch the legs of 9mm ammunition. Hitting small targets at moderate ranges can be a great capability to have in a PCC or a subgun. 

Primary Arms GLx 2X Prism sight acss gemini
A 2X prism on a PCC? Trust me, it works. (Travis Pike for TTAG)

From a tactical perspective, a human threat is fairly large. However, human threats have human brains and, in a gunfight, usually make themselves as small as possible. This can make a threat at 50 yards difficult and at 100 yards almost impossible to hit with a red dot. The 2X power of the GLx 2X prism gets you a fair bit closer and makes hitting that small target easy. 

At the same time, the optic needs to work at close ranges. At super close CQB and PCC ranges, you need a big reticle and eyes opened shooting capability. The GLx 2X prism seems to offer exactly what I need and want. 

The Primary Arms GLx 2X Prism In Hand

The design of the GLx 2X prism promises all the features I want in a magnified PCC optic. It’s lightweight and simple. The optic weighs 11 ounces and is 5.3 inches long. Prism optics often have a short eye relief, but the GLx 2X prism comes with 3.5-inches of eye relief. It’s not perfect (nothing is), but generous for the optic type. The eye box is present and an issue, but it’s fairly generous.

Primary Arms GLx 2X Prism sight acss gemini
The GLx provides dayight bright illumination. (Travis Pike for TTAG)

The reticle is big, illuminated, and shines brightly even at high noon. The prism has 11 brightness settings with three-night vision settings.

I live in Florida, it’s spring, and the sun sits high and bright. The illumination in most prisms is challenged by a bright, sunny environment. However, the GLx 2X prism stands up well under the bright sky of Florida. The illuminated reticle is beyond daylight bright and captures the eye well. 

ACSS reticles kind of rock, right? I enjoy them quite a bit, and the Gemini 9mm reticle is designed to function with a variety of PCC-type weapons. This includes 16-inch barreled rifles and 7.5-inch barreled subguns and SBRs.

The reticle features BDC-style holdovers and zeroes for both barrel lengths, and these BDCs go out to a rather generous 200 yards for a 9mm round. 

Primary Arms GLx 2X Prism sight acss gemini
It’s fairly compact and extremely easy to use at multiple ranges. (Travis Pike for TTAG)

At the center sits an illuminated chevron for a 25 or 50-yard zero. The chevron is surrounded by an illuminated three-quarter circle. Sitting below the chevron is two dots for extended ranges. The reticle is glass etched, and if the batteries die, it’s still in play. 

Strapping Up 

In the box, you get the optic, a series of Allen keys, as well as three risers. The risers give you a 1.64, 1.535, and 1.41 inch height, or you could run the optic riser-free. This makes it easy to mount the sight on nearly any 9mm weapon. 

I intended to find out and mounted the Primary Arms GLx 2X prism to a Taurus CT9. I zeroed the rifle at 50 yards as per instructions. The turrets aren’t fingertip adjustable, but the scope caps are slotted with the flathead tool needed to make adjustments. Those adjustments are both tactile and audible and very clicky. 

Primary Arms GLx 2X Prism sight acss gemini
Primary Arms provides multiple risers for use on a variety of weapons. (Travis Pike for TTAG)

Zeroing took a little longer than necessary because the elevation turret seemed to be set as low as possible. I needed to raise the elevation six inches to get halfway up the paper. With .25 MOA adjustments at 50 yards, it took plenty of clicks to get there. 

Shooting Near and Far

Let’s say I need to put half a dozen rounds on a target as fast as possible. Is the GLx 2X prism up to that task? What if the target is within 10 to 20 yards. With the illumination dialed sky high, I went after it. I put a Birchwood Casey 3D torso up and, with a timer, practiced my snapshots and my failure to stop drills. 

The eye box surprised me. It’s not just generous. It’s freakin’ Mother Teresa. I tried to mount the gun poorly, and it was tough to do. I tried to mess with my eye relief, and it was difficult to do it so badly that I couldn’t get a sight picture. The big bright reticle is easy to see and very easy to get on target. 

Primary Arms GLx 2X Prism sight acss gemini
The 2X magnification put me right in the face of the target. (Travis Pike for TTAG)

At close range, I used a two-eyed open occluded shooting style for close-range shooting. I could easily put 9mm pills right where I wanted them. That means good clean shots to the chest and well-aimed headshots. 

Backing up to 50, 100, and 125 yards, I got to make the most of that 2X magnification. At 50 yards scoring hits on a 4-inch gong was entirely possible. The 2X gets you fairly close and makes swinging that gong easy. At 100 and 125 yards, I could nail 8- and 10-inch gongs with boring regularity.

Primary Arms GLx 2X Prism sight acss gemini
The ACSS Gemini reticle is very useful and multi-purpose. (Travis Pike for TTAG)

At 100 yards, the bottom of the chevron is your aiming point, and it’s simple to score those accurate chest shots with the GLx 2X prism. At 125, I used the 150-yard dot and just hit a little high, but again it’s super easy. It gives me a fair amount of satisfaction to hit targets this far away with 9mm. I got a huge smile with every telltale ding. 

Clear and Ready

In the GLx 2X prism, we get super clear glass with excellent clarity. I can see everything, and it’s bright, vivid, and startlingly clear. The GLx 2X gives you a great sight picture for both near and far turrets.

The 2X magnification and ACSS Gemini reticle make it easy to hit targets far beyond normal 9mm range with exceptional accuracy. Up close, the optic offers a generous eye relief on top of a deep eye box. 

The Primary Arms GLx 2X prism fits my needs perfectly for a PCC optic. While home defense can still be achieved by the red dot, the GLx makes it easy to turn your PCC into a multi-use weapon for multiple ranges.

Specifications: Primary Arms GLx 2X Prism Sight

Length: 5.3 inches
Weight: 11 ounces
Eye Relief: 3.5 Inches
Field of View At 100 Yards: 42 feet
Click Value: .25 MOA
MSRP: $369.99

Ratings (out of five stars): 

Reliability * * * * *
I’ve had zero issues on my CT9. The direct blowback design of the CT9 beats shooters up, but it didn’t cause a shift in zero for the GLx 2X prism. The reticle remained illuminated between shots and never even flickered. Plus, should the big EMP drop, the etched reticle means the optic will still work fine. 

Ease of Use * * * * *
If you want to drive your 9mm PCC or subgun out to extended ranges, this is the optic to do it with. Even at 125 yards, I consistently heard the ding. The prism is clear, bright, and easy to use. 

Overall * * * * *
With good eye relief, a massive eyebox, easy-to-use reticle, extremely clear glass, and a great price, the GLx 2X Prism with the ACSS Gemini reticle is a rock-solid optic. It’s not for everyone, but PCC nuts will surely appreciate it. Especially on rigs where a red dot and magnifiers currently take up too much rail estate. 


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      • Intro to competition carbine optic? Don’t hate the design but our version of the awb limits options this could be used with into irrelevance.

    • As with any BDC reticle you have to figure out what distances the holdovers are for with your loads. PA is secretive about their sub-tensions and won’t share reveal any more info than is in their advertisements. I find this stupid.

  1. “This can make a threat at 50 yards difficult and at 100 yards almost impossible to hit with a red dot.”

  2. This prism scope uses a CR2032 3V Lithium battery. What is the lifetime for the battery?

  3. Would be fun to use at the range and for plinking. Dig it. There is great joy to be had in nailing tiny targets with a PCC at 50-75 yrds.

  4. I have one on a 10.5″ .338 Specter mostly subsonic suppressed AR. IMO the chevron is tiny. I have old person eyes and depending on when I take my meds (which degrade my vision) I sometimes cannot resolve it as a chevron. I have found that pretty much everything else about this optic is as Travis says. I just wanted a red dot with no astigmatism issues and a little bit of magnification and this optic does that. Near my home (wooded, mountain side, lots of deadfall) LOS’s that you can actually shoot are rarely over 150yds. I almost never shoot beyond 200yds so 2x and the reticle are sufficient.

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