Primary Arms SLx MD-25 red dot review, test
(Photo by Sean Utley)

Primary Arms has been a long time go-to for firearms and general build accessories. Among its offerings is the SLx series of optics, which has become a standard for many shooters. The newest addition to that line is the Primary Arms SLx MD-25 Red Dot.

Red Dots, Rifles and the Primary Arms SLx MD-25

Micro red dot optics have become almost standard on AR rifles. They are small, lightweight and allow the shooter to engage the target with both eyes open. Overall, the SLx MD-25 is 3 inches long and weighs just 6.5 ounces.

There are some optics that claim a 30mm size, yet it appears they measure the outer wall of the optic and not the actual visible glass. The SLx MD-25, however, has a full 25mm clear aperture. It offers a wider field of view compared to other 30mm red dots. All this while being smaller and lighter weight.

Also, unlike most micro red dots on the market, the power/brightness knob is on the left-hand side. It features a high efficiency LED that offers a run time of 50,000 hours at a medium setting. There are 12 brightness settings in total—two of them for night vision use. The lens is fog resistant, which is a huge plus for those of us who often times start training at the crack of dawn and see sometimes drastic temperature and humidity changes during the day. The lens is also fully multi-coated and anti-reflective; this keeps it clear in a variety of lighting.

Next-Gen Features

While ARs are the most common home to micro red dots, they have become very common on a variety of guns. Primary Arms realized that and equipped the SLx MD-25 with its next-gen ruggedized mounting system. Integrated recoil lugs help lock the mount in place against the heaviest recoil, while large diameter cross bolts provide significantly improved clamping power. They will also hold up to significant torque.

Primary Arms includes a riser designed primarily for AR-15s and AR-10s, but it’s easily removable for installation on AKs, shotguns, and more. The included risers and spacers for mounting measure 0.96 inches, 1.41 inches, 1.54 inches, or 1.64 inches central height.

Primary Arms SLx MD-25 red dot review, range
(Photo by Sean Utley)

As I mentioned earlier, the SLx MD-25 boasts a 50,000-hour run time at the medium setting. I’m certain we’ll get more on the lower settings I tend to use. But that 50,000-hour mark equates to more than five years run time—that’s impressive. A common CR2032 battery powers the optic, making it easy when it finally comes time to replace it. No odd hearing aid battery or something you’re forced to order online.

Primary Arms SLx MD-25 Testing

What I personally like about the SLx MD-25 is that it has a very crisp 2 MOA dot. Serious shooters can appreciate having a dot that allows you a higher degree of precision compared to other 5 MOA dots. This is especially true once we start moving further and further from our target.

I always use fairly low power on my dots. The SLx MD-25 allowed me to get small tight groups at pace even when we started pushing the distances at the 2020 Athlon Outdoors Rendezvous in Idaho. I realize it’s a personal preference, but I like having the ability to have a more precision centric optic on my rifles.

SLx MD-25 Price

I could go on about the pros of this new offering, but one of the things that struck me most was the price point. The MSRP on the SLx MD-25 is only $169.99. I had to check twice to make sure it was right, as that’s an exceptional price range for this optic.

I found the SLx MD-25 to be a rugged and accurate red dot that held zero well. As a point of pride, Primary Arms shared with me that after rigorous field testing, this optic has been given a Silver-tier rating by the National Tactical Officers Association. My experience and the NTOA rating moves this optic into the serious equipment category. If you’re looking for glass in a more affordable price range, good luck finding much that compares to the Primary Arms SLx MD-25. For more information, please visit

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