Primary Arms SLX MD-25 Review: Best Budget Red Dot of 2020?

Primary Arms SLX MD-25 Review: Best Budget Red Dot of 2020?

Primary Arms has built its reputation on delivering solid entry-level optics. With each successive generation, the optics became more feature-rich and remained at the affordable end of the spectrum. Today they still offer entry-level optics as well as a few high-end models with ACSS reticle systems. The latest generation of PA optics has introduced us to the SLX MD-25 series of red dot. I received a demo model with no other instructions other than an all-clear to review. Let’s clear the air: We understand readers have been a bit vocal about overseas optics from China. The MD-25 is made in China and Designed in the USA by Primary Arms. TNR Reviews gear. We have no financial relationship with PA. If equipment makes its way into my lap, it gets reviewed. Let’s begin to check out the MD-25 and see if it stays true to form: high quality for low cost. Capitalism yo.

Fit and Finish:

Primary Arms SLX MD25 Review (29)

The MD-25 is a 25 mm red dot sight, which aims to offer a larger field of view over the micro-dots while keeping the weight and profile down to a minimum. Consider it a hybrid size between the full Aimpoint PRO and Micro T2 style sights. It’s a nice format for shooters who want more parallax-free wiggle room in challenging shooting positions. The sight is jet black with uniform anodizing with PA laser engraving and a recessed PA badge. The window is free of defects and the edges of the glass are free from excessive adhesive. The glass is lightly tinted to an almost imperceptible hue of blue. The interior of the optic is cleanly machined and the erector tube is scalloped to reduce reflection and glare. No dust or adhesive is noted in the optical body.

Primary Arms SLX MD25 Review (37)

The emitter is smooth and low profile; it is positioned at 9 o’clock. The machined windage and elevation caps are snug and loosen under o-ring friction which gives way to a smoothly threaded cap. The windage and elevation turrets are slotted to accept a coin or the inverted caps can be used. The tension from audible click to click is stiff but feels precise. Each click is .5 MOA. The rheostat adjustment feels slightly rubbery when turned, and the detents are not as defined between settings, but this is only a minor criticism. There are no dead spaces between each of the 11 settings and you won’t have trouble feeling each setting as you cycle through them. The rheostat sticks further out than competing brands, but with both eyes open this will not be a large concern.

Primary Arms SLX MD25 Review (32)

The mount is, by far, the best mount I have encountered in a budget optic. Comparing to the mount included with the Holosun series of optics, the MD-25’s mount is far more confidence-inspiring. The foot clamp is as wide as the mount and is secured by two large Torx head bolts which then thread into steel fittings on the other side of the mount. Included is some thread locker to secure the screws against vibration. The optic ships configured for absolute co-witness but can be converted to lower third (or higher) with the included spacers. Finally, the package includes a low profile spacer for other rifle applications.

Primary Arms SLX MD25 Review (31)

Overall, the package feels confident in its budget arena. When clamped to the receiver, the package feels solid and secure. With my Holosun, I felt the need to immediately find a new mount for the optic, but this will not be the case with the MD-25. I feel it is a more complete package.

The MD-25 In Use:

Primary Arms SLX MD25 Review (48)

I mounted the MD-25 to my Palmetto State Armory 10.5 inch kit. This is my budget build and I felt it was a good fit for the MD-25 as it represents a lightweight, basic rifle that does everything you need it to. The dot is crisp and bright, and at setting 9-11 it was visible at point-blank with 600-lumen weapon light-activated inside a dark environment. One thing of note is I felt the dot was cleaner and more round than my Holosun 403R which was a bit more of a streak. Unknown if this will vary from unit to unit.

Primary Arms MD25 (1)

Outside in the full sun, I felt most comfortable with the MD-25 at setting 11. The dot was bright and easy to find, though somewhat less bright than my Holosun on its nuclear setting. However, the nuclear setting on the Holosun was something I have never felt the need for. Indoors, the best setting to preserve battery life and still maintain usefulness with a weapon-light appears to be setting 9. With an advertised 50k hours of battery life at the medium setting, consider that battery life will be less than advertised if left on at a setting useful for self-defense inside the home.

The gun and dot felt almost too light, and it’s a pleasure to shoot such a lightweight and basic pistol. The whole package with optic, light, and sling is 6.6 lbs unloaded. The MD-25 was sighted in at 25 yards and I began testing. The dot was given multiple impacts from waist to shoulder height, and impacts from slamming the optic into the ground from a prone position and shooting between impacts. After each impact, I was able to ring steel both the 8-inch gong as well as the 3-inch gong (my skill notwithstanding) without issue.


After rough handling and impact testing, I took the optic to a water trough and let the optic sit for a few minutes. No air bubbles escaped from the MD-25 and upon removal, the optic appeared dry inside the body of the optic. For the remainder of my shooting session, no fog or moisture made itself present in the optic.

Primary Arms MD25

After the dip, I began to drop the optic on a firmer surface which was comprised of the 2×6 pier. I then returned to the 100-yard line to shoot the 100-yard steel and then confirmed my initial 25-yard zero with a sight-in target. The optic remained dead on and held zero. Throughout my range session, the MD25 exhibited drama-free behavior.

After my first range session, I realized I forgot to test the parallax shift, so I headed back to the range for a quick test. I moved the dot in the window between 3, 6, 9, and 12 o’clock positions and I was able to ring steel easily (minus my missed shot). The MD25 continued to exhibit good behavior during parallax testing.

Wrapping Up:

Primary Arms MD25 (2)

The MD25 is a robust, no-frills entry-level red dot. At a retail price of $169 it would do well to help outfit several builds with a robust optic while keeping prices low. The mount is of particular interest, as it will not need replacing immediately as it appears overbuilt. This is not the case with some competitors where I felt the need to replace the mount immediately. At this price, I would give these an all-clear if you are looking for a budget red dot option. The mount and larger viewing window certainly tip the scales when comparing similarly priced budget red dots. My only complaint involves the rubbery rheostat, but that rubbery feel is likely due to a good O-Ring seal. It certainly did not affect performance in any manner whatsoever. PA continues to refine its red dot with each generation, and this one continues the tradition of high value for a low cost.

Now for the elephant in the room: Perhaps one day PA and other manufacturers will shift production away from China, but for now, the best budget red dots appear to come from China and other Asian countries. Primary Arms is an American company that has pushed to improve the performance of overseas optics, and on that front, they have been improving upon and delivering solid entry-level optics for years. The embarrassing display from Leupold shows us that an entry-level “assembled in USA” red dot cannot compete in price, features, or perhaps even durability. To get better products, you’re going to need to spend much more money. That’s a decision you will have to make for yourself, I just review things, man. It’s what I do.

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Lothaen OUT

Written by lothaen


  1. M.B. Pagal · May 27, 2020

    Designed in USA, eh? I’d suppose they could easily invest/outsource quality manufacturing in India, Nepal, or Vietnam as well. Let’s hope they do, they’d sell a lot more that way.

  2. Mike · May 27, 2020

    It’s unfortunate that the powers that should not be have sold US out, we are now lacking the good jobs, stagnant wages or have the means of production 🏴.
    Good article, products like these may be our selvage

  3. MD Froman · October 23, 2022

    “After my first range session, I realized I forgot to test the parallax shift, so I headed back to the range for a quick test. I moved the dot in the window between 3, 6, 9, and 12 o’clock positions and I was able to ring steel easily (minus my missed shot). The MD25 continued to exhibit good behavior during parallax testing.”

    What distance and what size steel?
    The big booger nobody wants to flick is that most of these sights intended for Home-Defense/CQB are parallax corrected starting at 25 Yards and stretch that out as far as 50 Yards and it’s INSIDE that distance where the Home Defender, LEO, etc is getting 8 inches of Parallax Shift when forced to fire from tight cover or unorthodox shooting positions.

    When shooting a defensive MSR/MSP at legitimate CQB distances we are already compensating for height over bore and aiming 7 inches high at anything inside of a residential structure or office building. Now add 6-12 inches of parallax shift because you’re trying to clip a bad guy down a hallway which hiding behind a staircase with a weird rail so your eye is in the far upper left quadrant of the glass and you could have multiple complete misses under stress despite being 100% fast and deadly standing up square on a nice flat training range with your eyeball perfectly centered in the optic while maintaining a textbook stance.

    I’m not picking on this optic specifically but on the way the gun press avoids giving Parallax Shift more attention and explaining it to novices who have not run an RDS in combat or even if they have never realizing why their hit percentages were so low that had to fire a whole magazine to hit a single hostile at 15 yards and don’t make the hit until they have changed firing positions and gotten perfectly centered on their optic.

    I’ll give you mad props for even mentioning Parallax Shift though because the entire gun press is avoiding that subject like the plague anytime a manufacturers sends them a new optic to gush over(thanks).

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