Holosun 510C

Holosun 510C: Best Value Red Dot Sight? [Hands-On Review]

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It might be the trigger finger that sends a bullet downrange, but the eyes ensure it’s right on target. And what better optical aid do we have than a red dot? It makes target acquisition a lot quicker, which can be a total game-changer. 

While red dots are a joy to use, the good ones usually come with a hefty price tag. Holosun tries to challenge this with its line of affordable products. One crowd favorite is the Holosun 510C, an open reflex red dot sight. Is it worth our time and money? That’s what we’re set to find out in this review.

  • Quick target acquisition
  • Small and lightweight
  • Three reticle options
  • Unlimited eye relief
  • Clear lens, crisp reticle
  • Easy to attach/detach
  • Two power sources (solar & battery)
  • Shake Awake feature
  • Recoil resistant
  • Good price, great value
  • Non-ambidextrous buttons
  • Mid-range use

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What’s a Reflex Sight?

Holosun 510C: Best Value Red Dot Sight?
Holosun 510C: Best Value Red Dot Sight?
Holosun HS403C (tube-style) vs Holosun HS510C (open style) from Amazon

A reflex sight is one of the three categories of red dot sights. The other two are prism and holographic sights. Each of these types uses different systems to provide better target acquisition.

Reflex sights are the most common of the bunch. Some even interchange the words “red dot” and “reflex sights.” What’s important to remember though is that all reflex sights are red dots, but not the other way around. 

From the word “reflector,” reflex sights work by projecting LED light onto a lens. This light is reflected by the lens in the form of a red dot, which we use for targeting. Reflex sights are either tube-style or open/exposed. 

Tube reflex sights have a form that makes them look like mini riflescopes. They make use of two lenses. The light hits the rear lens first, then it reflects on the front lens before reaching your eyes. 

The other type, open reflex sights, only have a single lens so the emitter is exposed. The light is projected onto the front lens which, in turn, reflects back to our eyes. Red dots of this type are quicker and lighter than the tube-style version. 

Getting to Know Holosun

What’s one way to identify a young company? Easy, there’s no Wikipedia article about them. Or maybe Holosun didn’t bother. Whatever the case is, Holosun Technologies is a relatively new player in the optics industry—but judging by their optics, it is a company that has already learned a lot.

Holosun was established in 2013. The secret ingredient for their success isn’t really much of a secret. They make quality optics more affordable, and gun enthusiasts like me are more than happy. 

It’s also not a secret that Holosun products are China-made. This answers why their red dots cost way less than US-based brands like Trijicon and EOTech. Though some prefer US-made products, many have become more accepting of Holosun as a whole. A big part of this is the company’s innovative design and technology. It includes the Shake Awake and Solar Failsafe features, among others. 

They make red dot sights, lasers, lights, and other related accessories. Holosun also manufactures the affordable line of SIG Sauer Romeo5 red dot. One of their most talked-about products is the Holosun HS510C.

Holosun HS510C: Open Reflex Red Dot Sight

Holosun 510C: Best Value Red Dot Sight?  Holosun HS510C: Open Reflex Red Dot Sight
Holosun 510C and a Sig Sauer Juliet 3 magnifier flipped to the side.

Though rare, some things can offer many features in such a small package—and the Holosun HS510C is one of those.

Double power sources, check. Shake Awake, another check. The list goes on, and I’m happy it practically ticks all the boxes on my must-have list. With the Solar Failsafe feature, there’s no need to worry about a blinking reticle spoiling the fun at the range. 

This trusty open reflex sight is suitable for both rifle and carbine platforms. It runs in two modes: manual and automatic. I can shoot with confidence knowing that the solar panel does its job with the brightness.

There’s no more fumbling with the buttons. Not that it’s a bad thing, I live for those when operating it manually. Still, we can’t deny the convenience of a red dot in auto mode.

Aside from the specs, another number we’re all happy about is the price. 

It costs way less than the Vortex AMG UH-1 Gen II (MSRP: $799.99) and EOTech EXPS3 (MSRP: $749.00). It makes sense since these two are holographic sights. Still, usage-wise, we can hit almost as many targets with the 510Cs. 


The Holosun HS510C is housed in durable aluminum with a titanium hood. It’s corrosion and wear-resistant, thanks to the micro-arc oxidation (MAO) coating process.

Reticle2 MOA dot
65 MOA circle
Reticle colorRed
Light wavelength650 nanometers (nm)

With the Shake Awake feature, it quickly springs to action the moment you grab the gun. Aside from the 2 MOA red dot, there’s also the 65 MOA circle for close-quarters engagement. Most of the time, I want it all, so I opt for the combination of the two.

Holosun 510C MOA

The red reticle comes in 65 nm wavelength. It works best around 100 yards and below. It isn’t magnified, but that’s a given since it’s not made for long-range use. 

Dimensions3.3x1.68x1.78 inches
Weight4.94 ounces
Window size0.91x1.26
Adjustments per click0.5 MOA

The small profile of the Holosun HS510C is also something I really like about it. Since it’s an open emitter, it is impressively light, weighing only 4.94 ounces. It has a square window common among holographic sights so feast your eyes with a great field of view. 

To zero, the elevation adjustment screw is located at the top behind the solar panel. Windage is located on the side. Each click corresponds to 0.5 MOA. Adjustments can be made up to a maximum of ±50 MOA.

Power sourceBattery/Solar
Battery typeCR2032
Battery life20,000 to 50,000 hours
Brightness settingsDay: 10
Night: 2

This red dot sight runs on dual power: battery and solar. It comes with a CR2032 battery so you can try it the instant you receive it. Battery life is around 20,000 hours with both the dot and circle on. It can last much longer with the dot only.

Switch modes once indoors and manually adjust the brightness. To make sure it isn’t overly bright or low, you get 12 brightness settings for this red dot. You can make up to 10 adjustments for daytime, the rest is for dark nights. 

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First Impressions

Holosun 510C: Best Value Red Dot Sight? Holosun 510C red dot and circle reticles
Holosun 510C red dot and circle reticles (from Palmetto State Armory customer gallery)

Aside from the sight, the box includes the usuals: manual, lens cloth, Allen key wrench, and a CR2032 battery. They also included tools for adjusting windage and elevation and for removing the battery tray. The QD mount is already in place which makes installing it much easier.

This is one expensive-looking sight that looks as rugged as it is presentable. The MAO finish does wonders in the durability department. This tough guy is also impressively light, even with the QD mount on, weighing only about 7.5 ounces.

The Holosun HS510C didn’t come with the battery on. However, that didn’t stop the red dot from staring back at me right out of the box. It draws power from the solar panel by default and adjusts brightness as needed. Like most open-style red dots, the glass has a bit of a tint. In this case, it has a bluish tint to it.

For manual operation, the buttons are easy to locate on the left side. I wish they were ambidextrous though. I guess it’s a needed compromise given the compact profile of this sight. The battery tray goes in on the other side of this optic, so no chance for buttons there.

Mounting and Installation

Holosun 510C: Best Value Red Dot Sight? Mounting and installation
(from Giphy.com)

The Holosun 510C is easy to mount. It fits any Picatinny rail out there. It’s the kind of product you don’t have to reach for the manual to install. The quick detach system made removing it very instinctive as well, which is a good thing since I’m planning on using it on another platform as well.

Push the locking button, mount it on the rail, lock the lever, and you’re good to go. If it’s too tight or too loose, adjusting the Torx socket will do the trick. 

Bringing the battery onboard is no different. It’s located on the side, and I was able to get it inside in no time. The tray is securely locked with bolts on both sides.

Installing it shouldn’t take more than a couple of minutes. Also, since the controls are located on the sides, putting a magnifier behind will not get in the way of operating it. 

Setting It Up & Operating It

I went through the manual this time for the operation and setup. The Holosun HS510C packs a lot of features and I don’t want to wait for the Eureka moment to discover them all. Plus, the faster it’s set, the sooner I can hit those targets. 

The plus (+) and minus (-) buttons work for changing the reticle brightness settings. Since there are no other buttons around, they’re also responsible for all other functions. 

By default, this red dot sight runs in auto mode. Holding down the plus button for three seconds changes it to manual operation. Doing the same with the minus button changes the reticle type. I like to run it with both the dot and the ring in auto mode. However, when it’s on battery and when not needed, I’ll just stick to the humble dot to save battery life.

You can set the Shake Awake for 10 minutes, 1 hour, or 12 hours. I didn’t bother changing the 10-minute setting that it comes with. It’s good enough that it almost feels like it is always on while saving power when not detecting any movement. Holding down both buttons turns off the red dot for storage, but mine won’t be needing this feature anytime soon. 

Range Time

Holosun 510C: Best value red dot sight? Holosun 510C with the + and – button on the left side
Holosun 510C with the + and – button on the left side (installed with a Sig Sauer Juliet 3).

The Holosun 510C fits most rifles and pistol-caliber carbines. 

The reflex sight was pre-zeroed so I only had to do a bit of adjustment on windage and elevation. With the sun out, the auto mode did a good job with the reticle. It demands attention and my eyes naturally gravitate to it. It was quite crisp and solid, and I didn’t notice much of the bluish tint on the glass. Parallax was non-existent too. 

I tried it at 10 yards first and it was nothing short of precise at short ranges. Next up was around 25 yards, and targets still proved accurate. Another great thing was that it didn’t budge with rapid-fire shots. It clung to the Picatinny rail like magic, even after a hundred rounds or so. 

The circle-dot combo was easier to follow than just the red dot alone, especially at around 25+ yards. The ring made transitions from target to target real smooth. 

There’s no need to worry about eye relief with this little red dot. We can shoot with both eyes open, and the image stays clear. This is also a big plus for situational awareness. 

As a reflex sight, it is more astigmatism-friendly than other red dots. Since I don’t have stigmatism, I let a buddy of mine try it and he was all smiles after that. He didn’t get the usual “starburst” and smudge—but what I’m sure he’s getting is a Holosun 510C for himself. 

It’s one thing to hear about how tough this sight is, but it’s totally another when you see it torture tested. I want to keep mine so didn’t feel like putting it through the wringers. Fortunately, the Alabama Arsenal guys did it for us. See it dropped, submerged, and frozen in the video below. They even mounted it on a 12-gauge shotgun.

Other Red Dots to Consider

If you want the Holosun 510C in a different color, you should try the Holosun HE510C-GR. It’s basically the same optic but with a green 540nm reticle. Since it’s green, it costs a little extra too.

The Vortex Optics Razor is another open reflex sight for rifles and PCCs. Dot size is either 3 or 6 MOA. It is waterproof, rugged, and has seamless construction with its single-piece chassis.

Let’s not forget the Leupold DeltaPoint Pro. It’s a compact 2.5 MOA sight that provides a great field of view. Made with military-standard construction, this is also one tough sight to have.

For platform flexibility, the Burris FastFire II is a good choice. It has a 4 MOA dot reflected on high-grade optical glass. It’s waterproof and heavy-duty, yet very lightweight. The small profile of this red dot makes it suitable for just about any gun.

Magnifiers…Because Why Not?

The Holosun 510C is amazing for short-range shots. However, if you want to stretch the distance to 100+ yards, then consider getting a magnifier. Since this is a budget-friendly sight, it would make sense to also pair it up with affordable yet quality products. 

The Holosun 3x HM3X makes a great duo with the Holosun 510C. It mounts the same way as the sight. It has a nice flip-to-side mechanism. Field of view is its greatest strength, which is 37 feet at 100 yards. It provides good vision, good color, and ultimately, good shots. 

For a more compact magnifier, the first thing that comes to mind is the Sig Sauer Juliet3 Micro. It is easy to attach and even easier to use. Aside from the form, another thing it boasts about is the undeniable crystal clarity.


The Holosun 510C is not a perfect red dot sight, but in a non-perfect world, it’s one of the better ones. I was pleasantly surprised by how durable and premium it is. It offers quality and performance at a reasonable price—which is what “best value” exactly means.  

Looking for more red dots? Check out the 5 best parallax-free red dot sights today. For your rifle needs, you might also want to check the best AR-15 laser sights on the market. 

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Featured image by sunghooter from Reddit

1 comment
  1. Might be worth adding a review of Holosun’s trash warranty policy. An optic is only as good as 1 – How well it withstands real world conditions, 2 – The manufacturer’s willingness to stand by the quality of their product, especially when things go wrong.

    In my experience Holosun falls apart in these categories making it a subpar, tacticool item of little or no practical value. Certainly not worth the cost!

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