The landscape of “budget” optics has sure changed over the last decade or so, with many new companies producing ever better, higher-quality options at affordable prices. Primary Arms is one of those brands that has established itself and earned a firm foothold in the market by bringing good looking, perfectly serviceable, often quite feature-rich optics to the masses. One of the latest is this SLx MD-25 Microdot, and it’s pretty darn great.
Included in the box with the SLx MD-25 is a low base (seen on its own to the right in the photo above), a standard riser for centered/absolute co-witness with typical AR-15 sights (seen above installed on the optic), and two spacers: thick and thin (not pictured). The thin spacer provides a 1.535-inch height to center, which I believe is Aimpoint’s standard height, and the thick spacer nets a 1.64-inch height for that lower 1/3 alignment of your iron sights.
Along with the mounts and spacers is the necessary hardware for each available option. While most optics would have you purchase mounts separately, the MD-25 comes with every conceivable option right in the box. Plus tools, a cleaning cloth, and a user manual.
Quite the comprehensive kit for its very reasonable $169.99 MSRP. If you’re lucky enough to pounce when one’s available, there are sometimes even open box and blem units available for about $40 less. Either way it’s a heck of a deal.
Mounts, by the way, match the Aimpoint Micro (T1/T2) pattern so there are lots of other options out there in case you want to go QD or otherwise get fancy.
You may have noticed that the SLx MD-25 isn’t a typical microdot. Rather, it occupies approximately the standard footprint of a microdot but in a larger diameter format.
At the expense of weighing in about 2 ounces heavier than a similar-sized microdot, it provides the large field of view of a 30mm, full-size red dot scope but does so in a smaller, lighter package than what you’d find in that category.
Rotating the left-side knob in either direction clicks between 11 brightness settings, including two night vision-compatible levels, plus “off.”
The MD-25’s single CR2032 battery resides within this knob, and the sight will run 50,000 hours off that single battery (at medium brightness). That’s pretty awesome. That’s 5.7 years. From a $1 battery (if you pay for a nice one).
Also visible in the photo above, the inside of the MD-25’s ocular bell is threaded to accept flash hiders or other caps.
Under the nicely knurled elevation and windage turret caps are easy-to-adjust turrets with clean, crisp, audible, half-MOA clicks with 50 total minutes of adjustment each. The rectangular bar on the top of each cap can be used as a tool to turn the turrets, but you aren’t likely to need it as the turrets themselves are serrated along the edges and easy enough to rotate by hand.
Thanks in a big part to the easily swappable mounts, the Primary Arms SLx MD-25 immediately found a home in my testing rotation. Within the first month I had run it with the low mount on a few of our Pork Sword Pistols in various calibers.
I had run it low mounted on a Radical Firearms RF/22 during the Franklin Armory 22-C1 Binary Trigger review.
I ran it on AR platforms in .22 LR, 9mm, 5.56, and 300 Blackout. Including machine gun use:
In all cases the MD-25 was just what the doctor ordered. It has a crisp 2 MOA dot (it would just cover a 2-inch diameter target that’s 100 yards away) with a full brightness range appropriate for use from dusk to dawn, including in the full Texas sun where many dots really struggle to show up.
Note that in the fourth photo in this review — the one that shows the dot — 95% of that “starburst” look to the dot and the reflection inside the edges of the optic is something I couldn’t prevent my camera from showing, but it’s an effect of the camera, not actually something your eye sees in the optic. Unless you’re in a fairly dark environment running the red dot cranked up to 11, the MD-25 has about as nice and clean of a precise little red dot as they come.
While fully multi-coated, the SLx MD-25’s lenses impart far less color shift than most red dots and provide a nearly neutral, clear view that’s much closer to naked eye vision than the norm.
Side note: I’m wearing the same hat and t-shirt in both videos and in the photo above, yet all were taken not just on different days but in different months. I clearly need to expand my wardrobe.
Speaking of wardrobes, the SLx MD-25 is pretty enough for any occasion. It has that high-end look to it with an appealing design, clean machining, and an even, deep, hardcoat anodized finish.
Over many months of regular use on all sorts of different firearms, the MD-25 has been a rockstar for me. It retains zero without fail (and has even proven its ability to return to zero after removing it and later returning it to the same gun), has a precise enough dot for accurate shooting out to a couple hundred yards, is daylight bright even in full Texas sun on a light background, provides a very wide field of view with nearly no color shift, and comes right out of the box with all of the mounting options necessary to work on just about any firearm.
The Primary Arms SLx MD-25 is a no-brainer, solid choice for a fantastic red dot at a killer price.
Specifications: Primary Arms SLx MD-25 Microdot
Reticle: 2 MOA Dot
Brightness: 11 settings (including two night vision) plus “off”
Dot Color: Red
Click Value: 1/2 MOA
Adjustment Range: 50 MOA
Battery Life: 50,000 hours at medium brightness
Battery Type: CR2032
Material: Aluminum
Finish: Hardcoat anodized
Weight: 6.5 ounces
Warranty: Lifetime
MSRP: $169.99
Ratings (out of five stars):
Utility * * * * *
When you combine two mounts, two spacers, plus all the hardware and tools necessary right in the box with a 2 MOA dot, wide-field-of-view optic you nail five-star utility.
Form Factor * * * *
Good looks with excellent machining and finish. It looks nicer than its MSRP would suggest.
Optics * * * * *
Clear glass and a crisp, stop sign red dot with plenty of brightness adjustment. At this price point the optics quality is five stars for sure.
Durability * * * * *
While I didn’t torture test the MD-25, others have and it’s clearly a stout, well-made optic. In my testing I found the turrets to track true and the zero retention was flawless. All components appear well-made and everything fits and functions correctly and confidently.
Overall * * * * *
I simply have no gripes or nit-picks to level at the SLx MD-25. While, sure, I could request enhancements such as “off” clicks between each of the brightness settings, a QD mount(s), or flip-up lens caps, at an MSRP of just $169.99 I’m fully five-stars happy with this fantastic, large diameter microdot.