Primary Arms SLx 1-6x24 Gen IV review

By the OpticVerdict Editorial Team.
Research-based review · Updated 2026-07-23

How we reviewed it: a research-based review built from the retailer specification sheet and the verified owner-review record, read lowest rating first so the criticism is not filtered out. We have not bench-tested this unit ourselves; the score is our editorial opinion and owner ratings are shown attributed to their source. See how we evaluate.

Check the part number first

Before anything else: OpticsPlanet lists at least five different scopes called SLx 1-6x24. This review is the Gen IV, part numbers 610181, 610182 and 610183, at around $350 . The others are the older Gen III at around $290, an SLx 1-6x24 IV Tube model, a separate 30 mm Tube listing and the cheaper Classic Series, and each carries its own review record. That matters when you are reading reviews anywhere, because the Gen III has more than three times as many as the Gen IV, and those are not evidence about this scope.

What it is

The SLx line is Primary Arms' value tier, and the 1-6x24 Gen IV is its low-power variable optic for an AR-15: a 30 mm tube, a 24 mm objective and a second focal plane reticle, which keeps the reticle the same apparent size at every magnification so it stays fast at 1x and readable at 6x. The reticle is the point of the scope. ACSS Aurora builds bullet drop compensation in 50-metre steps out to 800 metres, moving target leads for speeds to 40 mph, and 5 to 10 mph wind holds from 400 to 800 metres into one system, and the alternative ACSS Nova Fiber Wire strips that back to plain mil or MOA ticks that work with any load.

Why owners rate it: the illumination and the 1x

The recurring praise is unusually specific. An owner who lists Burris, Cabela's, Swampfox, Vortex, TruGlo, SIG and other Primary Arms LPVOs among his previous scopes says illumination was the biggest failing of all of them and that this is the one that fixed it. Another describes the Nova dot as bright enough to use in full sun on snow, so the scope genuinely works as a red dot at 1x, which is the whole promise of an LPVO and the thing budget models usually fail. Beyond brightness, owners report good eye relief, positive clicks, a light weight for the class and clarity that is very good in the centre. One competitor running two of them on a 14.5 inch Daniel Defense carbine reports no failures through desert and mountain use including drops onto rock, and says that inside 100 yards his target acquisition time with this scope is almost the same as with an Aimpoint T-2, while being clear that it is not built to ACOG or Specter DR standards. That is an owner's assessment, not our test, but it is a considered one.

“NOVA dot? Wonderfully bright! You can actually use this on 1x as a red dot. Full sun on snow and you can still see the dot… Image is super clear in spite of the edge distortion.”

Yeah thats me (ME), via OpticsPlanet

The honest catch: the eye box at 6x

The clearest limit, and the reason we hold this at 4.2, is the eye box at the top of the magnification range. Multiple owners describe the same thing in different words: at 5x and 6x, if your head is not exactly where it was last time, the picture shades heavily or goes black. One owner puts the tolerance at about a millimetre of movement, calls it workable for deliberate precision shooting and unsuitable for fast acquisition, and wonders whether he received a bad unit since his other Primary Arms optics are excellent. Alongside that come smaller honest complaints: the reticle is a little thick at 6x and can cover small targets, there is visible distortion at the edges of the image, the magnification throw lever is stiff out of the box, and two owners describe the illuminated dot as not perfectly round, appearing as a cluster of small dots to one and simply too bright for an owner with heavy astigmatism who prefers low settings. None of these are hidden by the 4.6 average; they are what you accept at this price.

“The reticle is a little thick at 6x and can obscure small targets, the eye box is not very good at 5-6x and causes a fair amount of shading in the glass if your eye is not perfectly aligned.”

Blue Max (AL), verified owner, via OpticsPlanet

Trade-offs, plainly

• The eye box is unforgiving at 5x and 6x, so shading and blackout punish an inconsistent cheek weld.
• The reticle is thick enough at 6x to obscure small targets.
• Owners report visible distortion toward the edges of the image and glass at 6x that is decent rather than excellent.
• The magnification throw lever is stiff out of the box.
• No mount is included, so add a 30 mm cantilever mount to the real cost.
• It is a full-size 1-6x, and one owner found it too large for an 8 inch barrelled 300 Blackout SBR.

Key specifications

A note on what is missing from that table. The retailer's specification sheet for this scope does not publish a weight, length, eye relief, click value, adjustment range, waterproof rating or illumination-setting count, so we do not print any of them rather than fill the gaps from memory; the one eye relief figure in the owner record, about three and a half to four inches, is a single owner's measurement and is treated as such. On awards: this scope carries no editorial award. "Best budget LPVO on the market" is the headline a customer put on his own review, not a prize and not our claim, and OpticsPlanet's "Best Rated Product" badge is a store rating.

Should you buy it, and what else to consider

• Buy it if you want a daylight-bright illuminated LPVO with a real holdover system for an AR-15 at around $350 , you shoot mostly inside 300 metres, and you can build a consistent cheek weld.
• Want a mount included? The Sig Tango-MSR picks in our best LPVO guide ship with a cantilever mount, which changes the real price comparison.
• Want a first focal plane reticle? The Vortex Strike Eagle family holds true at any magnification; see also FFP vs SFP explained.
• Want the premium version of this idea? The EOTech Vudu 1-6x24 FFP is the four-figure first-focal-plane 1-6x, with a more forgiving reputation at 1x and its own honest catches around daylight illumination and weight.
• Comparing 1-6x Vortex options? Read our Vortex Venom 1-6x24 review.
• Not sure an LPVO is right? See LPVO vs red dot.

FAQ

More: best LPVO · best scope for an AR-15 · Vortex Venom 1-6x24 review · LPVO vs red dot · best rifle scopes.