Primary Arms SLx 3x32mm Gen III Prism Scope [2022 Review]

Cover Photo Credit - Primary Arms...

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Primary Arms SLx 3x32mm Gen III Prism Scope [2022 Review]


Cover Photo Credit – Primary Arms

Primary Arms 3x Rifle ScopePrimary Arms ACSS SLx 3×32 Gen III Prism Scope Check Price

I finally got the chance to do a test and review of the new Primary Arms ACSS SLx Gen III 3x Prism Scope, and I’m excited to showcase the features of this amazing mid-range optic.

This rifle scope is a new 2020 addition to the Primary Arms SLx optics line. Although heavy, it’s a finely-constructed prism scope whose vision and impeccable glass quality make it feel like a downright steal when you weigh the characteristics against the price.

Given all the feedback from videos, discussion boards, and forums, folks are having a field day pushing this prism scope to its durability limits. But, I’m also glad to see customers with astigmatism praising the overall brightness and visibility of the optics.

Personally, I’m more than satisfied with what the Primary Arms ACSS 3x Prism Scope has to offer. I’ll talk about the prism scope’s characteristics and visibility in detail, where it exceeds expectations, where it flops, how it handles short to long-range groups, and its overall ease of use.

If it doesn’t prove to be a fit for you, I’ll also throw in a couple of alternative scopes for you to try out.

Let’s get right to it.

The Manufacturer’s Idea

A US brand of impeccable reputation, Primary Arms is a known supplier of high-quality accessories for AR-15, long-range rifles, and modern sporting rifles. They provide all kinds of customization options for both civilians and law enforcement.

Their SLx 3x prism sight is quite a mouthful: “Primary Arms SLx 3x32mm Gen III Prism Scope” with an ACSS 5.56 CQB M2 reticle. ACSS stands for “Advanced Combined Sighting System”, and CQB M2 stands for “close-quarters battle”, implying that it’s made for AR-15 rifles and modern sporting rifles.

Check out our roundup of the best 15 AR-15 rifles for 2021, if you’re looking for our top AR-15 rifles for this year.

With this product, Primary Arms wanted to go for a hefty prism scope with solid durability, extreme weather sustainability, easy adjustment and zeroing, and high-quality lenses that are suitable for competition shooting and defensive purposes.

Primary Arms somehow managed to design a budget-friendly rifle scope with all the necessary components that can appeal to both rookie and seasoned modern sporting rifle enthusiasts.

Undoubtedly, the SLx 3x32mm Gen III Prism Scope is a proven successor to the Gen II of the same line of rifle scopes.

Primary Arms SLx Gen III 3x32mm Prism Scope – Overview

Primary Arms 3x Rifle Scope
Source: Primary Arms

The Primary Arms Gen III 3x Prism Scope is the highly anticipated newcomer to their SLx lineup that features 3x and 5x prismatic optics.

Throughout 2020, this budget prism scope has seen solid success for the manufacturer. It offers all the important features and necessities that constitute a high-end prism scope, and I still can’t understand how the price is so low.

There’s also the ACSS-CQB 300BLK/7.62×39 variant, which is for the .300 AAC Blackout round, but we’ll focus on the 3x ACSS 5.56 CQB M2.

Speaking of which, here’s an in-depth buyer’s guide for .300 Blackout magazines, if you’re interested in bullets longer than the 5.56.

Whether you are a hunter, recreational shooter, competitive shooter, or you’re just looking for some long-distance recreational fun, this prism scope will prove a valuable item within your optics arsenal.

I can safely say that the Primary Arms SLX 3x Prism Optic can stand its ground as a towering competitor to the Vortex Optics Spitfire 3x Prism Scope, which is one of the best budget scopes (prism scopes, that is). Here’s why.

Design and Durability

The Gen III 3x prism scope and its mounts are well-tested in abusive field conditions and are practically designed to withstand all kinds of weather and/or human errors. They pretty much knocked it out of the park in terms of mid-range precision shooting.

Primary Arms claims that they used high-quality materials for manufacturing the prism scope and that they’re twice as strong as most of their competitor’s scopes. This is in no small part owed to the Type II hardcoat hard-anodized, aircraft-grade aluminum construction with a black anodized matte finish.

Though it might be heavy for some, it’s pretty lightweight for a prism scope, weighing 16 ounces. It’s shockproof, fog proof, IP67-rated for waterproof functionality, and can take a beating. I mean, it did survive being run over by a Jeep.

Additionally, it’s worth mentioning that the Primary Arms Gen III 3x Compact Prism Scope has the seal of approval by the National Tactical Officers Association. It has passed inhumane field testing with flying colors and has been awarded a “recommended” rating.

Magnification and Optic Quality

Here’s a little secret. Most of the manufacturing cost for rifle scopes is directly related to the glass alone. Basically, 80% of the total retail price is quality control, and it’s rarely due to the extra features and design.

I know that most riflemen aren’t fans of fixed magnification optics, but this one is something different.

As we said, the Primary Arms SLX Gen III scope is a prism-style optic. The focusing prism delivers light to the ocular lens far better than the traditional lens scope system, which makes this a very good option for those with slight visual impairment and/or astigmatism.

Just like standard prism scopes, the SLX has a fixed magnification setting—3x magnification with a crisp and clear 32mm objective lens. The focus dial is located on the eyepiece.

The fixed scope gives you some confidence and comfort with a 31.5 ft FOV (field of view) at 100 yards for easy target leading. The scope’s surface has anti-corrosion and anti-glare properties as well, so it won’t give away your position.

The ACSS Reticle

The Primary Arms SLX prism scope’s reticle is a center chevron reticle with BDC. It’s a highly-detailed ACSS reticle with several holdover points which enhance accuracy, especially for moving targets.

This is a decent scope for leading, thanks to the special “leading points” on the reticle. The horseshoe shape is also great for close-quarters engagements in my honest opinion. It’s a powerful standard, even more so when configured for CQB with the familiar horseshoe ring.

It offers decent target acquisition, holds 5 MPH windage, and it has a BDC system (bullet drop compensator) with hash marks that help you hit moving targets up to 600 yards away. The BDC holdover points are for when you’re fast-tracking or aiming long-range.

The reticle can be illuminated. Thanks to the multicoated lenses, the light transmission offers excellent brightness, and the reticle is visible during broad daylight.

Personally, I kept it simple and went with an entire reticle, mid-range target practice, but it’s still viable for long-range. The reticle should be accurate enough for the 5.56 caliber, .308 Winchester, and the 5.45×39 as well. You’re more than welcome to try these other calibers out yourself.

Looking for budget rifle scopes, here’s our roundup of best rifle scopes under $500.

Eye Relief

Here’s where this scope annoys me.

The Primary Arms Gen III Prism scope has 2.72-2.92 inches of minimum eye relief, and this is a bit short for me personally.

Needless to say, an eye relief of 3 inches at the very least should be obligatory; otherwise, it’s too low for comfort.

I think it would be fine for most users if you can keep the range calculations precise, as it can be pretty hard to assess the distance, especially if you’re using a heavy recoil rifle.


The reticle is illuminated in red by a LED, powered by a single CR2032 battery that provides 11 different levels of illumination. You can change the settings via the designated dial at the top of the scope’s tube. The battery is located on top of the scope behind the elevation and illumination adjustment turret.

Another downside, however, is that none of the illumination levels are NVG-compatible (night vision goggles). Although, this isn’t much of a bad thing because the battery can go up to 3000 hours of runtime if you have the illumination set on low.

The SLX Gen III 3x prism scope also comes with two removable lens covers and a set of tools that you’ll need when installing the mount riser.

Check out our roundup of the best red dot sights for AR-15 for 2021.

Mounting Options

The SLX Gen III 3x prism scope is equipped with next-generation ruggedized mounts with large diameter crossbolts for enhanced clamping power. The integrated recoil lugs lock the mount in place, and you can blast away without worry.

It comes with a removable MIL-STD 1913 Picatinny rail and a near-indestructible, thumbscrew mounting base that’s compatible with both Weaver or Picatinny-style bases. You also have extra mounting space if you want to place an ancillary unmagnified red dot.

Additionally, it’s compatible with standard carry handle mounts for both AR-15 and AK-47 rifles. You got your removable and durable proprietary riser with decent durability and the removable spacer that allows height adjustment similar to AK-47 or AR-15 platform standards.

Check out our best rifle bipods for 2021, if you’re looking for some stability in your hunting sessions.

Optimal Range

Its fixed 3x magnification, the bright illuminated ACSS 5.56 CQB-M2 reticle design, wind leads, moving target leads, and BDC up to 600 yards put the Gen III’s ideal range at around the 300-yard mark with just the right amount of wiggle room.

Either way, it’s a viable option if you want to hit targets up to 600 yards as well, all thanks to the great lens and BDC hash marks, though it still depends on the rifle and caliber you choose.

Windage, Elevation, and Parallax

Much like most of your modern scopes, the SLx Gen III has windage and elevation adjustment turrets with decent stability and tactile feedback for enhanced ease of use. The windage and elevation adjustment turrets have an audible “click” and are super easy to adjust.

The capped, ¼-MOA-per-click turrets are easy to zero and allow a 60-MOA reticle adjustment range for both windage and elevation.

The turret caps aren’t lockable but are secured by the rubber holders and they don’t budge easily.

This might be a small detail, but it’s extremely important. How many times have you accidentally rubbed your fingers on these while you were fine-tuning the brightness and you lost the elevation settings?

Parallax compensation is already built into the lens and prism system of the optic, and it isn’t necessary because the magnification is fixed.


Manufacturer Primary Arms
Focal plane Prism Scope
Magnification 3x, fixed magnification
Objective lens 32mm
BDC reticle ACSS 5.56 CQB M2 GENII, Illuminated
Eye relief 2.72 to 2.92-inches
FOV 31.5-feet field of view at 100 yards
Battery CR2032 3V Lithium Coin, 3000 hours low-mid level
Adjustment click value 1/4 MOA
Mount M1913 Picatinny
Total elevation adjustment 60 MOA
Total windage adjustment 60 MOA
Turret Features Capped turrets, tool adjustable
Mount Mounting base for both common styles
Weight 16 ounces

Pros & Cons


  • CQB-optimized horseshoe chevron reticle
  • Bullet drop compensation and highly convenient moving target leads
  • Durable, field-tested, and approved by the National Tactical Officers Association
  • Strong mounting system with stable clamps
  • Viable up to 600 yards
  • Fully illuminated reticle is visible even in bright daylight
  • Suitable for 5.56 NATO/.223 Remington, 5.45x39mm, and .308 Winchester calibers
  • Lifetime warranty


  • Not very pleasant eye relief (more than 3 inches would have been decent)
  • Non-night vision compatible
  • Fixed magnification might not be suitable for some

What Do Others Have to Say?

Here are some interesting testimonials and review snippets from customers that bought the.

youtube awesome review thank you
Source: YouTube
this or other prism sights like vortex ones
Source: Reddit
as an astigmatism
Source: Reddit
primary arm phenomenal all arounder
Source: Primary Arms

Alternatives to the Primary Arms SLX Gen III 3x32mm Prism Scope

Check out these alternative prism scopes that are of similar quality to the Primary Arms SLX Gen III 3x32mm.

Vortex Optics Spitfire 3x Prism Scope

Vortex Optics - Alternative

The Spitfire 3x Prism Scope comes very close to the Primary Arms SLX 3x Gen III, and they’re pretty much neck-and-neck in accuracy, ease of use, adjustability, and durability.

It has a 30mm and 40mm multi-height mount system, and it allows for holdover with an optimum range of up to 500 yards. It’s shockproof and fogproof thanks to the o-ring seals, can withstand heavy recoil, and the dual Picatinny rails allow for you to pair it with an auxiliary reflex sight of your choice.

The Vortex Optics Spitfire proves its mettle in the close to medium range and offers excellent target acquisition thanks to its EBR-5.56B (MOA) reticle with five intensity levels. It’s suitable for the 5.56 x 45 cartridge when rapid shooting and target leading is in question.

This prism scope has fully multi-coated lenses with anti-reflective coatings, and offers a slightly better vision in low light conditions, in comparison to the SLX Gen III.

Monstrum S330P 3X Prism Scope


Lastly, I’ve heard nothing but good things about the Monstrum S330P 3X Prism Scope. It’s a heavy (15 ounces), yet compact (only 5 inches long) prism scope with a 3x-magnification objective and 40mm tube housing.

The construction is well-made, and the optic is shockproof, waterproof, and fogproof.

The etched, military-style ACOG reticle is available in red or green with multiple brightness levels, ideal for rapid target adjustments and for CQB close-quarter applications. What’s great is that you won’t need power to illuminate the reticle in normal lighting conditions.

Taking into consideration the size and weight, I’d recommend this for your light AR-15 with a short receiver.

Conclusion – The SLx Gen III 3x32mm Is an All-Rounder Budget Prism Scope With Essential Features

If you need a durable prism scope that can handle heavy recoil and is easy on the astigmatic while shooting from 10 yards all the way up to 600, the Primary Arms SLX 3×32 Gen III is a cost-efficient scope for both rookies and seasoned competition shooters.

Although the eye relief could use improvement, it has all the necessary features, adjustability, and ease of use for a do-it-all AR-15 rifle scope.

It’s a fixed magnification scope and it’s heavy like a regular prism scope, but I’m fairly positive you’ll find something that will greatly appeal to your shooting style.

It has the right amount of magnification and adjustability, while the ACSS-5.56-CQB-M2 reticle offers daylight bright illumination and superb target leading features. The optics are phenomenal and highly durable, even in wet and foggy conditions, making this a decent hunter scope.

Overall the SLx Gen III is a very durable scope that’s rigorously field-tested, and Primary Arms offer a lifetime warranty just to be sure.

Brady Kirkpatrick

Hi there, I'm Brady and I'm the owner of I have been an avid gun enthusiast and hunter since I moved to the Midwest over 15 years ago. It's my passion to share my knowledge and expertise to help you find the best guns in your price range.

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