Primary Arms SLx3-18X50 (Image courtesy JWT for
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With the SLx 3-18×50 FFP rifle scope, Primary Arms has deliveredsolid, feature-filled optic at an outstanding price point…exactly what people have come to know and love the company for.

The glass quality of this SLx line scope is very good. Looking through it and some of my 20-year-old Leupold scopes, this Primary Arms glass is the clear winner. It’s amazing how far Chinese-made scopes have come and still remain so inexpensive. At 800 yards the glass remains clear enough, edge to edge, to reliably range and engage targets as small as 10″

It does well in low light, but not quite as well as the SIG SAUER Whiskey6 3-18x44mm I liked so much. Then again, that scope is significantly more expensive. As it is, the Primary Arms SLx 3-18x50mm was good enough to identify the difference between a buck and a doe, or to aim precisely at either one at 400 yards past the legal daylight hunting hours in Texas.

Image Courtesy Primary Arms.

There are several reticles offered with this series and magnification range, but this particular scope includes what I think is the best of the bunch, the Athena BPR MIL reticle.  It provides a great deal of information and everything is marked in a way that I can quickly understand and reference easily. It’s also got a center chevron aiming point, a feature I wish I had on every scope I own.

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This is a first focal plane scope, so the reticle can be used to effectively range at any magnification. The reticle completely fills the view at 10X.

Image courtesy JWT for

The parallax and illumination knobs, as well as the magnification adjustment ring were very difficult to move right out of the box. After a day’s use on the range, they all loosened up quite a bit and now function perfectly. They can all be adjusted without too much pressure while behind the gun, but stay in place once adjusted. The magnification adjustment ring comes standard with a removable quick-adjust lever.

Image courtesy JWT for

It’s easy to reset the zero, and the elevation turret includes a zero stop as well. The adjustments move easily, with a solid feel and audible clicks. Big, quick adjustments don’t require you to come off of the gun to make them. Both windage and elevation are well marked, and the elevation includes turn indicators as well.

Image courtesy JWT for

The SLx 3-18×50 ships with both a set of marked turrets and a set of capped turrets.  Genius. If you want to run all capped or all marked, you can. But if you’re like me, (and probably a whole lot of other people, too) you dial for elevation but hold for wind. So mix and match the turrets (as above) and you’ll never have to worry about bumping or accidentally moving the windage turret. It’s one less thing to worry about.

In order to test the precision of the optic, I mounted it on a Kiote LRP chambered in 6mm ARC. I’m still not sure how precise that particular gun can be, but I’m sure it will do better than .3 MOA. With the SLx3-18×50 mounted in Leupold rings, the turrets tracked beyond my ability to accurately measure them.

On the tall target test, I also verified the hash marks in the reticle line up where they should within the margin of error for the rifle, shooter, and ammunition. I performed a simple box test and just fiddled around with the turrets a bunch and returned them to zero. All adjustment controls passed with flying colors.

Image courtesy JWT for

Primary Arms scopes are almost always feature-packed and it seems like they’re usually illuminated. That’s the case for the SLx 3-18x50mm. The illumination has been done right. First, it’s truly daylight capable. Take a look at the photo above.

That’s not the clearest photo (the multiple lenses on the new phones make filming through optics a challenge), but you can plainly see the bright red reticle. Illumination is on the next to highest setting and it’s ridiculously hot and bright outside in that photo. Primary Arms also did the illumination settings correctly by placing an “off” between each setting position.

Image courtesy JWT for

Running the illumination settings on top of the parallax adjustment has become pretty standard, but in this particular instance it makes for an unusually wide footprint. The scope measures 3½” wide from the outside edges of the illumination adjustment and windage knobs. That width is because Primary Arms has decided to use a fairly wide and double-knurled knob set on both the illumination and parallax adjustment knobs. The downside is a bit more width, but the upside is that both knobs are easy to manipulate even with cold, wet, or gloved hands.

Mounting the optic in a Primary Arms GLx 30mm cantilever scope mount with a 20 MOA cant, I put the scope in the deep freeze overnight. The next day I mounted it on top of a new Stag Arms 15 Pursuit (review pending). The scope worked just fine, which means it went from 106 degree heat to zero to 108 degrees within 24 hours and ran without issue.  I also dunked it in the sink for half an hour without a problem and no fogging.

Since neither the Kiote LRP in 6mm ARC or the Stag Arms 15 Pursuit in 6.5 Grendel have much recoil at all, I also mounted the scope on the Ruger SFAR in .308 and ran a few magazines of M118LR. The reticle didn’t move a bit.

Image courtesy JWT for

The overall quality of the SLx 3-18×50 is outstanding. It’s durable and feature-filled, with a glass quality that’s far above what you would expect at this price point. It also comes with Primary Arms’ lifetime guarantee.

SPECIFICATIONS: Primary Arms SLx 3-18x50mm FFP Rifle Scope

Battery Type: CR2032 3V Lithium Coin
Click Value: 0.1 Mil
Exit Pupil Diameter: – Low: 16.20 mm / High: 2.70 mm
Eye Relief Low: 3.90 in / High: 3.50 in
Field View: 100 – Low: 36.70 ft / High: 6.10 ft
Focal Plane: First Focal Plane
Length: 13.2 in
Magnification: 3X; – 18X
Objective Diameter50mm
Total Elevation Adjustment: 14.5 MIL
Tube Diameter: 30mm
Zero Reset: Locking
Width: 3.5″
Length: 13.4″
Weight: 25.4 Oz
Price: $499.99

Overall * * * * 9/10
At a price of just under $500, the SLx 3-18×50 FFP is a great scope. The inclusion of the Athena BPR Mil reticle at this price point is even better. I took off something for the lack of low light coatings. If you have $500 and want to get the best long(ish) range optic for your money, this is it.

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  1. I have been looking at the 3-18×44 version of this scope and will now give this one a go for my .308 SFAR.
    BTW it is on sale on Amazon for $399 at the moment.

    • So you’ll happily pay Amazon now, to have Bezos and his Everytown for Gun Safety fuck us forever in the future. That’s a big HELL NO.

      • Have to agree with you there. I’d rather pay msrp or wait for Primary to throw it on sale, than send one red cent to that peckerhead Bezos.

    • Spend a little more, and buy Brownells MPO 3-18x50mm34mm(T) with Mils elevation 40, the time that I looked on sale $699.00. The scope has Japanese class, FFP.

    • Optics out of a PLA factory? That is a hard hell no.

      That a mfg is STILL in chicomland is a sign of lazy MBAs running the company. It is NOT 1990 when we thought the chicoms could be reformed and would become our friend. Go elsewhere.

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