Overview of the Holosun 403C Red Dot Sight

Guns used for any purpose, but especially for defensive use, will benefit from the addition of improved sighting systems, and in this era there is no better sighting system for fast and accurate shooting than a red dot sight, or RDS.

RDS tech has come a long, long way from its inception, and where once it was a rare and expensive piece of kit that was not highly reliable, it is today as common as anything else for firearms, available in a plethora of makes and models, each with different features, and at price points from flea market clearance bin cheap to mortgage payment expensive.

That variety means that not all sights are made equally, with each shooter having their own preferences and often festively arguing the perks and flaws of a given setup with their friends and associates. Among preppers, battery life is a major bone of contention, with some seeing anything less than a years-long lifespan as unworthy of investing in for long term survival.

Battery-free sights have been done before, but they all suffered from serious drawbacks in use or operation. One newer company, Holosun, has sought to remove the question of battery life entirely by equipping their flagship red dot sights with solar cells that can run the sight all by itself, and what’s more do so at a price point hundreds of dollars cheaper than top-of-the-line competitors.

Now the question is “do they work, and how well?” I undertook the task of shaking out one of their solar sights, the HS403C, so you can be an informed purchaser. Dig into the details of this sun-harnessing sight below.

Why a Red Dot at all for Prepping?

A red dot brings the best combination of advantages for a defensive gun in most situations. They enable both-eyes-open, target focused shooting and typically allow the shooter to do so with the aiming point, or reticle, visible in all lighting conditions.

Most RDSs, even the larger modern sights, are small and light compared to more traditional telescopes, and especially when compared to most variable power telescopes, which can be quite bulky and hefty for their size.

While magnification allows a shooter to see farther and better, and so helps enable more precise shooting compared to iron sights or red dots, a scope’s biggest advantage, range, is usually squandered outside of a hunting scenario as in virtually every single case on record defensive shooting occurs in a highly compressed time frame at close ranges, overwhelmingly inside 20 yards, and virtually all of them inside 100 yards.

It is this range bracket where red dot sights excel, and for this reason you should seriously consider one for your survival guns

Drawbacks and Quirks of Red Dot Sights

Aside from lacking magnification for long or high-precision shots, the single biggest drawback of RDSs, if you want to call it that, is their reliance on batteries. While only a concern of cost for most shooters in kind times, the question of stocking and storing batteries for a long-term crisis is one of major importance for preppers.

Yes, some sights like the early Trijicon Reflex series do not rely on batteries at all, and illuminate the reticle by way of a fiber optic light transmitter assembly. This is a highly durable and long lasting system for obvious reasons, but not one that actually well suited to use in a variety of environments, as the brightness of the reticle is solely controlled by the ambient light at the collector.

So if you are shooting from a dim environment into a brightly lit one or on to a low contrast target, good luck finding the reticle. Similarly if you are shooting from a street at high noon into a dim alleyway or tree line, your reticle will bloom so brightly as to obscure more of the target than you need.

Neither situation is ideal, and having a reticle with brightness adjustable on the fly is a major perk, as one cannot say that what is ideal one moment will be inadequate the next; situations change. A battery powered optic will handily solve this issue, but depending on the type of sight and the battery you will be measuring runtime in a handful of hours to years, with the longest lasting technology on the market, as made by Aimpoint, commanding high prices for the privilege.

Batteries may not be that expensive (depending on the type) but they do slowly lose their charges over time, and are another failure point in the logistics train when it comes to preparing for SHTF.

What if there was a way to get the benefits of a battery powered RDS with the freedom from reliance on them as provided from a fiber-optic? Cue Holosun to the rescue.

The Holosun 403C – Features and Design Overview

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One of their most popular Holosun models and the subject of our overview today is the HS403C, an obviously inspired riff off of Aimpoint’s iconic T1/H1 Micro lines, only with the addition of clickable brightness controls on the right side instead of the Micros’ distinctive rheostats, and a top-mounted stripe containing the solar collector and sensor.

The windage and elevation knobs are also suspiciously similar to the Micro series sights, and once removed are mated into a corresponding slot on the adjustment turret to make adjustments. The 403C has plenty of adjustment range, approximately 50 MOA (or 25 MOA in any direction from dead center) and is achieved by ½ MOA clicks. The adjustments themselves are pretty positive, with a distinctly felt and audible click. This is a welcome change from most budget sights which have mushy, uncertain adjustments.

The entire sight unit so closely mirrors the form and function of Aimpoint’s Micro line that T1/H1 mounts fit the 403C perfectly. While the ethics of this are arguable, it is certainly a boon for the consumer as you will be able to partake of a far wider array of quality mounts than would normally be available for a more budget-oriented sight. At any rate, the 403C includes mounts that furnish both a lower 1/3rd cowitness on standard AR-15 receivers and a low-profile mount for other applications.

The entire sight is constructed from 6061 aluminum and finished in attractive satin anodizing. Holosun claims the sight can withstand shock in excess of 1000G’s and continue to function, though if the sight is ever subjected to that level of force you had better hope it is not in your hands at the time.

Holosun is a company that is carving a niche for themselves in the already crowded RDS market by addressing one of conventional battery-powered optics shortcomings while simultaneously keeping their strengths. They have achieved this lofty goal by adding a solar charging and control cell to most of their sights.

On the 403C, this integrated cell provides power to the LED and also controls the brightness of the reticle. More than that, they have married it to standard brightness controls that allow the user to override the solar sensor and turn the sight on and adjust brightness using a backup CR 2032 battery onboard the sight for the purpose. The CR2032 battery is common, inexpensive and efficient, and Holosun claims it will furnish up to 50,000 hours by itself, a claim to rival the years long battery life of Aimpoint.

By solar or battery power, the 403C provides plenty of brightness adjustment; 10 daylight, and 2 night vision compatible settings. The night vision settings were not tested under NOD’s, but I will point out that the brighter of those two settings was visible to the eye, and this means it will assuredly be far, far too bright for use with night vision equipment.

Of interest is the power switching system for the reticle. Any time there is enough sunlight to run the reticle, the sight is both powered on and brightness adjusted for ambient conditions. If it is too dark to power the sight, it will seamlessly switch to battery power and also engage an auto-off feature that will shut the sight off after a handful of hours.

The sight can be manually powered and adjusted by holding the “+” button, which will then allow the reticle to be dialed to the shooter’s preference. Of note is that Holosun produces several grades of sight in this family, each with more technology than the last. Upgraded models feature motion-on technology, what Holosun has dubbed “Shake Awake”, a dot-in-circle reticle as popularized by the EOTech HWS line of sights, and even green LED powered reticles.

All in all, a pretty nice package and features in a form factor most users of RDS’s will be comfortable with. The MSRP of the 403C is $235.00, and often streets for a little less.

The big question, as always, is: does it work? Read on to find out.

Impressions and Shakedown Results

Any of my longtime readers will know I am a big, big proponent of quality. Buy once, cry once and all that. Now, I do not believe you must necessarily buy every single piece of kit at a top-drawer price, but I treat firearms and related gear as life support equipment and buy accordingly. There is a price point at which you lose value.

I have noticed a distinct trend when it comes to optics and sight, and it is that most shooters who are willing to spring for quality guns even have a hard time spending half as much again on a sight of commensurate quality. Don’t know why, just something about it I guess and everyone budgets a little differently.

Me, I’d rather have a nicer set of irons than a cheap, shitty red dot, and so most of my coin on optics is spent on Aimpoint. Their sights are so good that they remain future proof for years, and that saves me a lot of cash over time. Nevertheless, I heard lots of good things about the Holosun sights, with even some of their ardent skeptics declaring them the best in their price range. So I set out and bought one, the 403C as discussed, to give them a whirl and see if they could impress jaded old me. Again, this was an off-the-shelf commercial purchase: the manufacturer did not provide one to me.

I have a small selection of ARs to use for work and play, and chose an older Colt 6920 for my test bed. This rifle has been boringly reliable and consistently accurate with my chosen loads, so I knew that out of the gate I would not have any trouble from the gun getting it zeroed and making hits. The sight came with a lower 1/3rd mount, as is my preference on an AR, so I decided to test the sight as-is, with a LaRue Tactical T1 mount standing by in case I had to trouble shoot any zeroing-related issues.

My standard procedure for shaking out an individual optic is 1,500 rounds before I declare it good, with 500 of those rounds spent on purely getting as much ammo through the gun as fast as possible in drills, with the remainder spread across training, competition and practice.

Zeroing proved simple; the clean adjustments made it a snap. Once that was done, I started shaking out the sight in automatic mode to test the auto-adjusting brightness with some simple drills on paper silhouettes and steel poppers. The day was clear, but some passing cloudy spots gave me ample experience with its dimming capability.

The sight handled fine and the reticle was crisp and clean, though the lenses had substantially more noticeable tint compared to the Aimpoint H1 I have used for ages. So far, so good.

The first issue was encountered after appx. 450 rounds or so; the sight kept intermittently shutting off, and no amount of sunshine would resuscitate it. I attempted to manually start the sight: no joy.

Undaunted, and because lemons happen, I decided to order one from a vetted retailer off the internet. A little expedited shipping later I had a replacement sight in 2 days. I followed my same zeroing procedure as previously and decided to run the sight through its paces for 200 rounds or so in preparation for an upcoming carbine class.

Regrettably, this suffered serious issues with brightness that became apparent after only 4 magazines through the rifle. The reticle would not illuminate past dim, even when keyed manually. This was gravely disappointing after I heard so many good things about this little sight.

That unfortunately concluded my testing.

Final Assessment

Bottom Line: I cannot recommend the HS403C after two back to back failures from commercially procured sights. My experience was contrary to what so many reviewers have said online, but definitely backs up my opinions I have long held about cheapo sights: at and around the $200 price point, the only games in town for decent quality are Vortex and Primary Arms. Otherwise, save your milk money for a better sight.

Whatever promise the solar cell technology may have for worry free use of a red dot in perpetuity, the Holosun 403C is not the one to crack the code, at least not for me. As I often preach, durability, and reliability are everything: if the thing cannot do what you bought it to do, what good is it?

While it obviously seeks to capitalize on the super compact tube-style form factor popularized by the Aimpoint Micro series, that is about the only thing they have in common. Sure, I’d love a T1 for $400 cheaper, but I’d also love to be 18 again, and that just isn’t going to happen.


Not recommended. The price is attractive, and I really like the solar operation in theory, even if only as a backup to a dead battery, but the failures with the two different examples I tried leads me to believe that not much has changed for the better in this price point.

Perhaps other models in the lineup, the more expensive ones, benefit from improved QC/QA. I hope that is the case, because though I really wanted to like the Holosun model I tried, I cannot endorse it at this point.

1 thought on “Overview of the Holosun 403C Red Dot Sight”

  1. I have both the 403C and a 503C. Other than the additional 65 MOA ring, the thing I like about the 503C is the motion on/off feature. Let’s you keep the scope on and ready when you grab it and go, without loosing the battery.

    The LED feature is great for saving your battery during the day.


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