Primary Arms SLx 1x Prism Gen 2- Can it Replace a Red Dot?

Primary Arms SLx 1x Prism Gen 2- Can it Replace a Red Dot?

compact enough to be unobtrusive, slick, and leave room for back up iron sights… if you insist on them. I don’t.

If you right click any photo, you can open it up full size for more detail.

Texas-based Primary Arms has released its second generation Cyclops 1x prism sight and I have had the opportunity to test a pre-production model for several months.  I’ll give you the bottom line at the top. Can it replace a red dot? I think it can, for several reasons…  and it has replaced them, at least for me.  I directly purchased several of these new prism optics to replace my own red dot sights.  This optic is a best-case hybrid between a mini-ACOG and an Aimpoint Mini-red dot. Let’s take a look:


The second generation SLx (Silver Line series) Cyclops is a 1x (no magnification) optic that uses a prism and lenses like an ACOG, but has a user-adjustable battery illumination like an Aimpoint for its etched reticle.  It uses the simple chevron and outer horseshoe ACSS reticle that was pioneered by Primary Arms.  The red reticle is daylight bright and can still be used if the battery dies or it is turned off. I believe a green reticle is also in the works. The illumination is auto-live, meaning it turns off after a while and will then turn on again with movement, and also features three night-vision settings. It is strikingly different from the first generation Cyclops, with a larger reticle inside, half the size outside, and a much improved mount and spacing system. The windage and elevation turrets are now recessed and uncapped, each giving a tactile 1 MOA adjustment per click.  The included robust mount uses two recessed clamping screws, has 8 different riser height options, an add-on AR carry handle riser (although one of the included risers will work for that too), and uses the mini-ACOG mounting footprint if an aftermarket mount is desired. Field of view is about 75 feet at 100 yards and the adjustable diopter allows an exact 1x magnification so that the interior image is seamless with the outside world.

Everything you need in the box, including a nice torx wrench and threadlock pre-installed on all the screws.

This shows the size of the reticle compared to the full field of view. the chevron is easily distinguished, unlike the reticle on the Gen 1 cyclops.

My pre-production model has seven settings. The Production model has ten.

Capless, streamlined turrets and an adjustable rear diopter ring.

Mini-ACOG mount footprint pattern

Two strong Torx cross bolts, three mounting bolts, all mating with steel integrated nuts, and two rail lugs. It’s not moving.

This specific carry-handle mount purchased separately sits the optic high enough to dial up the iron sights if you wanted to and has a channel to see them through the mount. The included high cantilever mount also has a see through channel and sits lower, so that works too.

Key Benefits

I want to highlight three qualities that make this optic superior in its class.  They are the etched reticle with adjustable diopter, increased image clarity vs a standard red dot, and user-adjustable brightness.  I am nearing 50 years old and wear glasses.  An optic is almost a necessity for me, and for years I went back and forth between a mini-Aimpoint and a mini-ACOG (TA-45). I was not satisfied with either one. The Aimpoint red dot allowed me to control the dot brightness and was superb for speedy work up close, but the image through the optic was relatively dim, the dot was out of focus due to my astigmatism, and if the battery died or had an electrical problem (which did happen once), I was bereft. The ACOG offered a brighter image (more on this later), and an etched reticle that was a bit more in focus, but I could not control the reticle brightness and had trouble when shooting from a dark interior to a bright target area.  What I needed was an optic that had the benefits of both systems with none of the liabilities, and the PA Gen 2 Cyclops does that.

First of all, the Gen 2 Cyclops has an easily seen, etched reticle with an adjustable diopter.  I did not know how much I needed an adjustable diopter until I actually looked through one. I have mild astigmatism that makes red dots look like a crooked Venn diagram.  The ACOG was an improvement, but the small reticle was still a bit blurry at the edges because it was made for a person with 20/20 vision and could not be made to focus exactly for my eye and prescription glasses.  With the diopter adjusted properly, I can get the Gen 2 Cyclops reticle as sharp as I have ever seen one, and the image exactly proportioned to be a true 1.0x, the image inside the optic seamlessly merging with the outside world.

Seamless 1x magnification

Secondly, the prism optic offers greater clarity of image compared to a red dot.  This seems to be contradictory at first.  Doesn’t a 1x red dot offer the same image that a 1x prism does, both having the same magnification?  In terms of image size, yes, but in terms of image clarity, no. The red dot does not focus or alter the path of the light that goes through the tube, it simply puts a dot on the target.  You only have as much light entering your eye as your pupil will allow, which is about 4 mm in diameter in daylight. A lensatic optic, like the Cyclops, collects light from an objective lens that is much larger than your pupil and “funnels” it into your eye… which is why a hunting scope with a very large objective lens is best for hunting at dusk as it makes the image intensity brighter, regardless of magnification.  I noticed this when I switched from the red dot to the mini ACOG years ago.  The image clarity seen at distance was greatly improved, more than just the 1.5x magnification could account for.  The detail that I could not see with the red dot, or the naked eye, was visible through the lensatic optic because the image was brighter, and sometimes this meant the difference between the ability to identify the target from the background or not.  You can’t effectively shoot what you can’t effectively identify.  The PA Gen 2 Cyclops has an objective lens of about 17 mm, meaning almost four times the size of your pupil.  Imagine your pupil opening up to the size of a penny; could you see better?  So even though they have the same magnification level, the Cyclops offers a superior image, which is bright and crisp.  See the comparison photo between the Cyclops and the Aimpoint in the section below if you doubt me.

at 250 yards. The reticle is blooming a bit, it’s so bright

All of these pictures, ALL of them, were taken with an old iPhone camera. The glass quality is even better in person.

And third, the Cyclops offers user-adjustable illumination.  This is the feature that is lacking with most ACOGs. The tritium-only and fiber optic ACOGs are fantastic optics until you try to use one looking from a dark location into a brightly lit area.  The reticle washes out and there is no way to reasonably make it bright enough to compete with the bright outside image. If the reticle can’t be seen, what good is the optic?  Also, sometimes outside in the sun, the ACOG’s reticle is too bright and it blooms.  I’ve seen “dimmers” that cover up the fiber optic strip for use in bright sunshine, but I’ve yet to see a “brightener” for the opposite problem.  The Primary Arms Cyclops gives an ACOG-like optic with the added benefit of constant and controllable illumination.

illuminated reticle in the full Florida sun, both in light and dark backgrounds

When non-illuminated, the reticle can disappear in a dark background

But with user controlled illumination, no problem

Range Report

I took the Gen 2 Cyclops to the range at least a half dozen times, both to indoor and outdoor ranges.  I sighted the Gen 2 in at an indoor range and zeroed the optic with a 50 yard zero at the top of the chevron per the instructions. Adjustment was easy with the large printed directions on the turret and tactile and audible clicks between settings. Next, I took it to a few local “action” matches that involved a lot of movement and targets within 25 yards.  It took a bit of thinking to mentally switch to using the larger horseshoe from the pinpoint dot of the Aimpoint, but very quickly I adapted and was running the Cyclops just as fast.  The image was clear and seamless with the outside world, and the daylight illumination worked fine here in the central Florida sun. Even though the Cyclops is not as nuclear bright as an Aimpoint, it does not have to be because the reticle has some thickness to it rather than just a single point. This makes it much easier to see than simply a pinprick dot. I don’t think I was lacking any speed compared to the red dot.  I also shot the Gen 2 Cyclops at 200 and 300 yard steel torso targets, both full-sized and reduced.  I was able to hit both the larger and smaller steel plates with ease, and to my utter surprise, I was able to hit a 12-inch round steel plate at 300 yards consistently shooting prone off a bag with some concentration and discipline.  The ACSS reticle holdover for 300 is spot-on.  I asked several other people to try the Gen 2 at 200 and 300 yards, both experienced and novice shooters, and all of them were able to understand how the reticle worked and hit the small plate.  One guy in particular was irritated that he could not buy one immediately since they had not been released yet. He wanted one NOW.

Awkward 200 yard engagement. No problem. The eye relief is very forgiving. I could mount it at the front of the receiver and have no difficulty.

300 yard line. A black full sized torso target is seen as a speck on the right side of the white sand berm. the 12-inch plate cannot be seen here, but it WAS seen, and engaged, through the optic.

Small torso target easily engaged at 300 yards

What follows is a direct comparison between the PA Gen 2 Cyclops and some other competitors in its genre.

Gen 2 to Gen 1 Cyclops:

The same manufacturer and same optic line?  Yes. Versus the Primary Arms Gen 1 Cyclops, the Gen 2 is superior in many respects.  The glass quality appears to be the same between the two, which is very good… but the Gen 2 is shorter in length, lighter, more streamlined, has a larger, and therefore useable, reticle, and has a more robust, adjustable mount.  One of the chief complaints about the Gen 1 was that the reticle was too small, so much that the inner chevron was effectively unusable.  As you can see, Gen 2 offers a larger center reticle.  More than just a superficial upgrade, the Gen 2 is a fundamentally reimagined and upgraded optic.

Notice the Gen 2 ring matches the size of the center ring on the target. I don’t know what the use of that observation is, but I did notice it.

PA Gen 2 Cyclops to Aimpoint

Versus the Aimpoint mini-red dot, the PA Gen 2 cyclops is superior in having an etched reticle that can be used without battery power, greatly increased brightness of the image, and an increased field of view. The Cyclops is also less than half the price of the Aimpoint.  The advantages I see for the Aimpoint is in proven ruggedness and in battery life.  The Cyclops might be as rugged, but that has yet to be seen, and it only offers 29k hours of battery life compared to 50k on this older Aimpoint.

Sorry about the Aimpoint OFF photo, but the illumination IS off, so good luck with that.

PA Gen 2 Cyclops to Bushnell Lil P

Versus the Bushnell Lil P, the PA Gen 2 Cyclops is superior in having a brighter illuminated reticle, brighter image due to a larger objective lens, larger field of view, and range finding marks.  The Lil P is significantly smaller and that is its key feature.  I don’t know of any lensatic sight that is as ridiculously small as the Lil P.  Unfortunately, Bushnell has discontinued it.

PA SLx Gen 2 Cyclops to PA GLx 2x Prism

Same manufacturer but different optic line? Let’s have a look. Versus the PA GLx 2x,  the SLx 1x Cyclops is superior in size and in speed when used in close-range shooting.  It is also much less expensive than the “Gold Line” optic.  The GLx 2x has better glass quality and higher magnification and is more suited for distance work.  My GLx 2x optic will go on a dedicated hunting rifle.


The Primary Arms Gen 2 Cyclops solves a lot of problems for me, and it’s now my go-to optic for a general-purpose rifle.  I’ve now bought several more since they have been released and they have replaced red dots. I no longer own my old TA-45 ACOG. Both the Aimpoint and the mini-ACOG are excellent optics, but the companies have been stuck in a rut for a while, living off government contracts and a well-earned reputation. They have not innovated and their features have remained the same for decades.  Companies like Primary Arms that have to constantly compete and innovate to stay in business have now taken these classic optic designs and have improved upon them.  I think this new Gen 2 Cyclops 1x prism optic merges the best features of the Aimpoint red dot and the mini-ACOG is therefore the best optic available for a duty rifle.

the optic can be found on Primary Arms’ website here

I trust the SLx Gen 2 enough to not use back up iron sights

Editor: Special thanks to PA for sending an optic for review. TNR has NO financial relationship with Primary Arms. We received no compensation for the above review. All thoughts are the authors and the authors alone. We do not receive referral income in any way shape or form, whatsoever, from PA or any PA-affiliated referral programs.

Thanks Theoden for another great review!

Written by Theoden


  1. Jim Hovater · July 20, 2021

    I’ll wait for the GREEN one!

  2. JustSomeGuy · July 21, 2021

    I too prefer a green reticle, but I’ll probably get a red one for now.

  3. john · July 22, 2021

    Do they have a magnifier 2x or 3x that will work with it?

  4. Theoden · July 22, 2021

    Yes, I have seen discussion where a magnifier will work, but I do not own a magnifier myself. Call PA and ask them to be sure.

  5. David Atticus · July 24, 2021

    In a Vortex discussion vid they advised against prism/magnifier combo use, chiefly due to diopter conflict issues, as i recall. Some fair info there, q.v. if interested.
    Would be nice though, wouldn’t it?
    I also heard some scuttlebutt somewhere re an upcoming release of a 3x prism from Primary which may be or not be the real deal. Green is the way to go, for my eyes anyway, but patience is a virtue i lack to any great degree! BTW, i own a Bushnell lil P scope and yeah, it IS tiny, and seems to be well made — works great, but at 11mm in diameter it is a bit cramped and a brighter image would be a boon, but it really is quite adequate and fit for purpose in most applications, for typical fairly close-in gunning. Not as quick as a RDS surely, but fast enough with practice on f/a ‘presentation’ consistency

  6. RSR · July 25, 2021

    Though heavier, the vortex spitfire Gen 1 on an ADM mount is the gold standard 1x prism in my book. Stupid fast reticle with circle in circle plus dot (but no ranging function/feature). Smaller circle at or slightly larger than the horseshoe in this PA Gen2 — hard to tell from photos, but inner circle might be thicker too on the Vortex.

    It’s a 25mm optic as well, which means brighter and larger FOV than these smaller ones.

    Swampfox’s 1x appears to be made by same folks as PA Gen 1, but features different reticle and buttons instead of a knob.

    PA Vortex Spitfire Gen1 also has both green and red illumination.

    For a compact pistol/sbr/pdw style lightweight build or when you need to have ranging, I do definitely think this optic has a place, but the Vortex Spitfire Gen1 is great for when you don’t need magnification or ranging like with home defense. If I need ranging or magnification for beyond 300 yards, I’m going LPVO though not 1x prism.

    Keep us posted on its mounts’ durability — all that lego adjustability seems like it might be a weak link.

  7. Matt Lohr · August 20, 2021

    I pre-ordered based on your recommendation using the link, but since you don’t get a kickback from PA, do y’all have a tip jar?

    • lothaen · August 22, 2021

      Our “tip jar” would be to click on the banners to brownells, mymedic, or PSA and order a thing. Those are our only sponsors. Thank you.

  8. Danny · August 26, 2021

    Question, any possible issue or concern with thermal drift of the zero ala Eotech? Perhaps something you can test?

    • Theoden · August 26, 2021

      Absolutely no possibility of thermal drift like the Eotech. The reticle is physically etched onto the glass.

  9. Austin · September 10, 2021

    What is needed to mount it to the carry handle in that picture?

    • Theoden · September 10, 2021

      Nothing extra is needed except maybe a thumbscrew, which is available on PA’s website. The see-through riser is included with the optic.

  10. Jim V. · September 11, 2021

    Fantastic review. Thanks for this. Will be picking one up as the only downside I can see to this optic is the 1 MOA adjustments. But with a 1x optic, that doesn’t bother me much.

  11. Austin Suter · September 11, 2021

    are you sure? it says on the pictures caption that you bought that mount separately

  12. Dion Bafundo · September 18, 2021

    Great read and info. I picked up one and love it..

    Will be changing out my red dots for this. Same issue older eyes with astigmatism.

    Dots to me look like supernovas without my glasses lol.

    Have the gen one also but retinal was to small even when focused.

    Thanks for the info again.
    Dion B.

  13. Gabe · September 18, 2021

    Where is it made? What country?

  14. Ferin · September 30, 2021

    How would this work as a 45° back up to an Acog

  15. Bob · December 21, 2021

    Can it be mounted to a carry handle directly without a mount or riser?

    • Theoden · December 22, 2021

      no, it needs a spacer to clear the rear sight. but it comes with a spacer that sits the optic very low and does not allow the use of iron sights.

  16. RJ · February 10, 2022

    Fantastic review! Since this is a new product I really needed to know how good it was. Compared to your review, the couple of other ones I read were almost childlike in comparison. Will get this for my new Mini 30.

  17. Paul Palumbo · September 5, 2022

    I have that the Cyclops 1x Gen 2 and the Vortex micro 3x magnifier. They work perfectly. The diopter conflict is well overstated in my opinion.

    I adjusted my Cyclops’ diopter first and then adjusted the magnifier to the Cyclops without issue. Again it works perfectly.

  18. Greg P · October 27, 2022

    Would the included mounts allow it to be mounted low enough to work on a “traditional” rifle like an 10/22 with a picatinny rail?

    • Theoden · October 27, 2022

      Yes, just use the optic and bottom mount with no riser. It would sit as high as any mini-dot. I think it would still sit high for a 10/22 with a standard stock, as the comb places the cheek in line with the very low iron sights, but would give a “jaw weld”.

  19. David Brown · November 30, 2022

    What company makes the mount you used to mount the slx to the carry handle?

  20. Matt · December 21, 2022

    I know I’m late to the party, but great review!
    Good job with the pics, showing bright & dark backgrounds.
    This has all the features that I was looking for in a red dot (green, in my case), but none of the drawbacks.
    Shake awake, etched reticle, brightness adjustable, mounting height adjustability, good glass, and sometimes the deciding factor – affordability.
    Thanks for the well written review!

  21. anonymous · December 26, 2022

    Thank you. This review is the most informative one. Others were mostly reciting the specs. I ordered the green version. Thanks, again.

  22. Paul · March 2, 2023

    This optic is very easily magnified. Yes two diopters are involved but it works flawlessly. I have a couple of set ups with the Cyclops Micro 1x magnified. 3x and 5x. No issues at all

  23. Paul · March 2, 2023

    like i said above – very easily magnified – I have it set up that I and use it without issue

  24. Dwight · July 12, 2023

    The lowest mount will be 1.1 inch above the rail for optic center.

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