Oh, man! It’s been over two years since I reviewed a rifle scope and over three years since I reviewed a LPVO (low powered variable optic)! That’s a long time. Probably eons in “internet time”. Which already makes this review a real treat. However, it’s also a real treat because it’s Primary Arms LPVO.

How so? I’m glad you asked. First off Primary Arms has been the largest sponsor of the blog for the past few years by supplying half a dozen pistol mounted optics and micro red dot. Additionally, the good folks over there have authored a few guest posts on this blog. And while I do have a financial relationship with them, where I get a small commission when a product is bought directly from their website after navigating there through a link on this blog, they have never once balked at any negative feedback I’ve written about their products in my reviews.

And that’s not where it stops. You see, Primary Arms has earned the reputation of being the Holosun of LPVOs. Meaning that they are rapidly innovating on LPVOs that are durable and affordable. As a result, I eagerly awaited to get my hands on their Gen IV SLx 1-6×24 SFP rifle scope as soon as they asked me if I was interested in reviewing it. For full disclosure, they provided the LPVO at no cost to me.

There are a couple of additional reasons I got excited about reviewing the Primary Arms SLx 1-6x24mm SFP Gen IV rifle scope, which I will refer to as either SLx, the scope, LPVO, or some combination thereof for the sake of brevity through the remainder of this post. The first reason is that it was recently awarded “Scope of the Year” in the 2024 Industry Choice Awards. The next reason is because I’ve learned a good bit more about rifle optics, including LPVOs, since I last wrote about them and a 1-6x magnification is now the community consensus as the sweet spot for LPVOs and it wasn’t until this opportunity that I would finally get my hands on a LPVO with a sweet spot configuration. Probably goes without saying, but my expectations for this budget friendly LPVO were high.

Did it meet my expectations? We will get to that in a bit. But first, let’s take a look at what one gets for $340 (at the time of writing):

• A scope manual,
• a reticle manual (in this case it’s for the SFP ACSS NOVA reticle),
• a lens cleaning cloth,
• a couple of hex key Allen wrenches,
• and the scope which comes with flip up caps, a modular throw lever, and a CR2032 battery installed.

There are a couple of discounted optional accessories available when purchasing the SLx scope from Primary Arms. The most obvious one will likely consider is a mount. There are several to choose from ranging in from from $50 to $250. Primary Arms was kind enough to provide me with the $75 option which is their SLx cantilever mount. Another accessory that I would probably consider is the discounted AutoLive Battery cap for $45 which will extend the battery life for those of us that perpetually leave the illumination on scopes turned on. The other options include a flip-up throw lever and a back up RDS mount.

Now that we covered what one gets and the optional accessories, it’s time to walk the 17.4 oz scope starting with the objective lens assembly that houses the 24mm objective lens. The housing itself is threaded to accept a sun shade. However, no sun shade was provided and I was unable to find one manufactured by Primary Arms that fits this SLx scope. I can’t say whether or not that will change in the future (assuming not finding one wasn’t human error on my part).

The objective housing seamlessly transitions into the 30mm main tube which leads us to the turrets and the illumination control knob.

Both the elevation (top) and windage (right) turrets are capped (as opposed to exposed) which is common for value priced rifle scopes. Capped turrets are my preference for LPVOs when combined with a reticle that allows for elevation and windage hold adjustments, which is the case with this SLx scope. With the right reticle there is rarely a need to “dial in” elevation and windage holds out to engagement distances where positive target identification is still possible with low powered magnification. There are other folks who prefer exposed turrets on LPVOs but the price points on those LPVOs are generally about an order of magnitude more expensive.

The low profile turrets don’t feel cheap which is a big plus for me. Each 0.1 mil click is undeniably tactile and audible which is a huge plus when dialing in a zero. Both turrets have numbered hash marks and the caps can be adjusted to realign hash values after zeroing with the smaller of the two included hex key Allen wrenches. The literature suggests that the total adjustment range of both turrets is 120 MOA. That’s kind of silly given the scope includes a MIL based reticle and adjustment turrets. Assuming I did the MOA to MIL conversion math correctly, the MIL total adjustment range is 35 MIL.

The illumination control knob is found on the right hand side. It offers 12 levels of brightness including a 0 or off position. Each level is silent, but tactile. It’s worth noting that the only part of the reticle that is illuminated is the center of the crosshairs which creates a red dot aiming experience. We’ll cover the reticle in a little more detail shortly (and most likely in more depth in a future post), but for now it’s worth noting that while the reticle illumination does achieve red dot brightness (as marketed) it doesn’t provide an illumination setting that is intended for night vision compatibility like many rifle red dots (even the more budget friendly ones) offer. At level 1 the “dot” is visible. Turning the volume up to 11, the “dot” is ridiculously bright and proved to be functional in the brightest environments that I tested it in.

The 30mm main tube continues behind the turrets. This part of the tube houses the majority of the erector assembly that begins at the front of the elevation and windage housing and extends just beyond the magnification or power ring and into the ocular assembly. The erector assembly is the heart of variable magnification power scopes. It houses two lenses that allow zooming in and out of the target. Any tolerance play or flaw in the assembly can cause all sorts of issues for the user including, but not limited to, significant point of impact shifts at different magnifications and parallax issues. I found no signs of either of those issues in my initial testing.

The texture of the power ring isn’t aggressive but it is usable. The removable modular throw lever makes magnification power adjustments even easier. Turning the power ring requires a modest amount of force, but the movement is smooth and easy to control.

Towards the end of the erector assembly which should be located just under the power ring is the ACSS NOVA second focal plane (SFP) reticle. The reticle design is interesting to me. I see it as a cross between a traditional duplex crosshair reticle, a MIL graduated reticle, and a bullet drop compensation (BDC) reticle. I’ll have to circle back on the reticle in detail in a future post to dive into it, but here are what I consider to be key features of the reticle:

• It’s a SFP reticle which means the reticle features will not zoom in and out like the objective image will and therefore features can only be used accurately and reliably at the highest magnification setting (6x in this case)
• With the illumination turned off, the fine cross hair allow for very precise aiming
• The MIL reference hashes along the horizontal crosshair can be used for windage holds or movement leading
• The MIL reference hashes along the bottom half of the vertical crosshair are graduated and can be used for ranging or elevation holds

While it’s not my favorite type of reticle it is well done and very useful. The red dot illumination is particularly well suited for rapid target engagement.

At the end of the ocular housing we have the ocular lens and the focus ring. The texture on the focus ring is a little more subdued than the texture of the power ring and there is less of it. This makes focus adjustments more difficult. This is a good thing in my book because it decreases the chance of inadvertent focus adjustments. Meaning that focus adjustments have to be more intentional.

I’ve already mentioned that the turrets don’t feel cheap. Well, neither does the rest of the scope. Honestly, I’m not surprised. The quality of entry level optics has continued to improve significantly over the years. Additionally, I can see why Primary Arms has earned the reputation of being the Holosun of LPVOs. The features make sense. The reticle design is well suited for common LPVO applications. There isn’t any one thing that screams budget on the SLx scope or anything that suggests it will not be durable.

Still I haven’t gotten to what most folks probably want to know, how well does it work?

I’m not gonna blow smoke up anyone’s skirt? It’s an entry level, budget friendly scope. A really good one, but it’s still an entry level, budget friendly scope at the end of the day. As such, I found some things that I would expect in a scope of this tier.

First, it’s not a true 1x magnification at the lowest setting. There is some magnification present at the 1x setting. Not a lot, but it’s there. This shouldn’t be a deal breaker. Even high end scopes have a little magnification present at the 1x setting. Getting a true 1x magnification is difficult when variable magnification is in play. That’s the reality of optics and physics. Generally speaking, the amount of magnification at 1x setting on a budget friendly scope is going to be more noticeable than it would be on a higher end scope. This was the case with SLx and it’s on par with what I’ve seen with other LPVOs in the same price range.

Overall image quality is great. That holds true until you get to the edges of the lens where there is a little edge distortion. Like the 1x magnification issue, this is common in this tier of optics. That said, unlike the 1x magnification issue, the amount of edge distortion on the SLx seems to me to be less prominent than what I generally see on other LPVOs in this price range. Just like the 1x magnification issue, these observations are entirely subjective as I have no means to perform an objective qualitative analysis. At the end of the day, I’m a guy with an eyeball that has probably spent more time behind optics than most other people, but I don’t have a laboratory where I can measure and record differences in refraction, reflection, diffraction, interference, or polarization.

Now that I’m done pooping on the SLx, I’ll end the review with a positive note or two. I mentioned the overall image quality is great and subjectively better than other scopes in this price range. Along with that I found that exit pupil and eye relief (sometimes collectively referred to as the eye box) to be very forgiving. This is in part achieved due to the physics of the 6x maximum magnification from  a 24mm objective lens that leads to the community consensus of 1-6x being the sweet spot for LPVOs. The reality is that more magnification decreases the size of the exit pupil and distance of the eye relief, requiring more precise positioning and alignment of the eye to use the scope effectively. However, the other part has to do with the execution of the reticle and image quality of the SLx scope in my opinion. The combination of a forgiving eye box, great image quality, and a functional reticle makes this particular LPVO very functional given. Especially when considering its price point.

Honestly, the Primary Arms SLx 1-6x24mm SFP Gen IV rifle scope is a strong candidate to dethrone the Vortex Strike Eagle as my go to recommendation for a functional, value priced LPVO. Whether or not it succeeds at that depends entirely on how it holds up as I continue to put it through its paces.

And that brings us to what’s next for this scope. What’s next is that it’s going on a budget rifle. Why a budget rifle? Well, most folks that ask me for a recommendation for a value-priced LPVO are looking for one to put on their budget build or rifle. So it makes sense to me from that standpoint. Furthermore, I happen to have an AR-15 that was provided by Bear Creek Arsenal that needs a review. Last but not least, the folks at Ammo To Go reached out recently and asked if they could sponsor the ammo for a review. This is like the perfect sponsored trifecta: AR-15, ammo, and optic. So yeah, that’s what I’m going to do and I’m going to do it soon. Be on the look out for that review and another post that dives deeper into the ACSS NOVA reticle.