Testing the Innovative Holosun SCS

in Authors, Garrett Negen, Gear Reviews, Optics/Sights

Estimated reading time: 7 minutes

Holosun SCS MOS on Glock 20
Holosun is pushing boundaries with its new micro-optic the SCS

Holosun is pushing boundaries with its new micro-optic the SCS. Having multiple innovative features, this optic is sure to do well.

As a junior in college, I was short on funds but needed a solid red dot for my AR. After a bit of research and a friend’s recommendation, I bought a Holosun HS403R. Six years later, that sight continues to function and I continue to look to Holosun whenever I’m in the market for a red dot. 

Holosun SCS Mounting Options

The SCS sets itself apart from other micro-optics by having each model’s footprint tailored to a specific gun. In my case, the SCS MOS is made to mount directly to a Glock MOS slide without the need for an adapter plate. Models designed to fit the Walther PDP 2.0, Sig P320, H&K VP9, and S&W M&P 2.0 are also available.

Mounting the Holosun SCS MOS on Glock 20

The direct optic-to-slide connection requires half as many screws as mounts that use adapter plates. In my mind, that means half as many opportunities for the optic to come loose or lose zero. The SCS nests perfectly into the optics cut of my Glock 20 MOS. The hefty slide of this 10mm is a bit wider than the body of the SCS but it makes no difference in its function. I checked the slide width of my Glock 19 and it matches the SCS perfectly. 

The deletion of the adapter plate also lets the optic ride significantly lower on the slide. In fact, it is low enough for the stock sights to fully clear the optic. I have always replaced the plastic Glock sights with metal ones but at least I don’t have to buy suppressor height sights to be able to cowitness through the optic window.

Holosun SCS MOS on Glock 20 on rock
Holosun is pushing boundaries with its new micro-optic the SCS

Not having to deal with adapter plates, getting a slide milled, or aftermarket sights really lower the barrier to entry when someone wants to get their first pistol optic. I have had first-hand experience with people becoming uninterested once they learn it isn’t as easy as slapping a red dot on their flat-top AR upper.  For those people, the SCS could be a simple plug-and-play solution. 

Solar Powered – SCS

The other feature that really sets this optic apart is in the name, SCS (Solar Charging Sight).  Holosun has been using solar cells on their optics for years but up until now, it has only been as a backup if the removable battery fails. With the SCS the solar cell actually charges a battery that is permanently encased in the optic.

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    Holosun SCS MOS on Glock 20
Holosun is pushing boundaries with its new micro-optic the SCS

    My main concern with a solar-powered optic is that one day I may draw my gun from a bag or other dark place and have a dead battery. After doing some research and tests of my own, I found these worries to be unwarranted. When fully charged the internal battery can power the sight for up to 20,000 hours depending on brightness and reticle selection. That’s over two years of life, and don’t forget, every time the solar cell sees a glimpse of light, natural or artificial, the battery will recharge. 

    Reticle Adjustment

    The SCS has three reticle options. First, A 32 MOA circle with a 2 MOA dot in the center. Next, just the 2 MOA dot. This is the most power-efficient and generally my favorite. Finally, the 32 MOA circle without the dot. The three reticles are changed by holding down the button on the side of the optic. After you cycle through all the reticles, the next press will turn the optic off. 

    Currently, the reticle just comes in green. The only reason I see to go with green vs. red is that our eye picks up the green color more easily so the dot doesn’t need to be as bright. With a tiny internal battery, I am sure they want to save power wherever possible. 

    Holosun SCS MOS on Glock 20 sight picture
    The sight body sits flush with the top of the slide.

    The brightness is not user-adjustable. The unit takes in ambient light levels and automatically adjusts the brightness accordingly. I am not usually impressed with auto brightness but this one generally does a good job. My only gripe is that it’s a little too bright for most lighting conditions. If it were a sight with manual brightness controls I would say it is about two levels too high. But, considering its role as a defensive optic, I would rather have my two MOA dots bloom out than have it too dim and not be able to see it in a bright environment. 

    SEE MORE: Holosun’s New Optics: Red Dots & Thermal/NV Hybrid Sights — SHOT Show 2023

    In the unlikely scenario where the dot is too dim, you can tap the button to activate the brightness override. Doing this will max out the brightness for half an hour. Pressing the button again will put the brightness control back in auto.

    Durability of the Holosun SCS

    A Grade 5 titanium construction makes the SCS both durable and lightweight. To test the optic’s ability to retain zero, I mounted it to my 10mm Glock 20. I figured the heavy recoil would accelerate any problems that may take longer to appear on a lighter recoiling gun. I only had one issue throughout my test. 

    Mounting Holosun SCS MOS on Glock 20

    Before I had finished my first mag, one of the mounting screws sheared off. The optic retained zero with the one screw it had left so I finished off the box of ammo before heading home. I was able to extract the broken screw and replace it with a new one. In retrospect, I probably overtightened them the first time. I have had no issues since. 

    Holosun SCS MOS on Glock 20 in water
    I submerged the sight for half an hour without issue.

    The unit has an IP68 immersion rating. This means that it can withstand submersion in at least one meter of water for at least half an hour. Unless you plan to go scuba diving with your carry gun, this optic should have no problem withstanding the wettest environments. 


    I think this is a good option for anyone who values simplicity. Easy mounting and no battery changes make this one of the easiest pistol optics to own and operate. The price is pretty reasonable too. The MSRP is currently $412 which is higher than most Holosun micro-dots but the others don’t offer the same benefits. 

    Holosun SCS MOS on Glock 20 on concrete

    All in all, I think the Holosun SCS is a winner. Visit Holosun’s Website for more information on this product or to purchase your own. 

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