It's been 7+ years since I purchased my first Holosun 510C.
In this Holosun HS510C review I want to be frank and just tell you why this is a good optic, and when its appropriate to use it and when it's not appropriate to use.
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Holosun 510C Core Specs
- Magnification - 1X
- Red Dot Reticle - 2 MOA + 65 MOA Ring
- Adjustment - 0.5 MOA / Click
- Brightness Settings - 10 DL&2 NV
- Battery Life - 50,000 hrs / 20,000 hrs circle dot
- Construction - Titanium hood
- Eye Relief - Unlimited
- Submersion - IP67
- Body Dimension -3.3" X 1.68" X 1.78"
- Window Size - 1.26" X 0.91"
- Weight - 4.94 oz
Unboxing

The box includes:
- Holosun 510C
- Manual
- Additional battery tray
- Cleaning cloth
- 1 CR2032 battery
- Allen key
First Impression on Holosun HS510C
The Holosun 510C red dot sight is DEFINITELY NOT a cheap sight like the Sightmark Ultra Shot Reflex sight.
When Holosun HS510C first came out, it was very easy for people to compare it with the Sightmark.
Now the 510C is right in front of me, and I can say it's a very rock solid product just by picking it up for the first time, very nice packaging, and a very good overall build quality and coating finish.
Other Holosun products all come in this standard packaging.
I think what you're thinking. This was the first ever open emitter sight that was big enough to compare with the EOTech since they have similar reticles.
But the 510C is an open emitter optic and it doesn't cost a fortune.
Holosun 510C Best Features
Window Size
The window size of the Holosun 510C is as big as an EOTech. Once the optic is mounted on a long gun, the field of view is very wide for any passive aiming.
The ideal optic to eye distance with the Holosun 510C is similar to any other optics as long as it feels comfortable to the shooter.
Reticle Options
The Holosun 510C's multiple reticle system comes with the following
The 2 MOA dot gives shooters a clean center dot for fast target acquisition and a precise aiming point for long-range engagement without covering up too much of a standard-size target. It's as small as a 1 MOA red dot but not so small that you can't see it.
A 68 MOA circle is the same as a 65 MOA circle
If you are not sure about the difference between 65 MOA and 68 MOA, they are actually the same circle dot reticle one measures the outer ring diameter and the other the inner ring.
In addition, the 65 MOA ring mode gives shooters a larger aiming reticle for fast target acquisition, and it's just fast for the eyes to pick up compared to a 2 MOA only center dot.
On top of that, the 65 MOA circle gives shooters range estimation capability just like EOTech's 68 MOA ring, and it can be used to represent a shotgun pellet spread pattern.
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Reticle Clarity & Brightness Settings
While most shooters out there have astigmatism, and a perfect sight might appear to have a starburst or smeared reticle reflected on the glass from the emitter.
So, I wore my glasses, and I also used my camera to check the clarity of the reticle. The result is that the reticle is very crisp.
Seriously, 20/20 vision fixes it all.
For shooters with astigmatism, the circle reticles will look blurry to some, but there are things you can do to counter that:
- Adjusting the brightness setting
- Co-witnessing the reticle through the rear iron sight peephole
- Use a bigger red dot
However, if none of these techniques have worked for you with red dot sights in the past, we highly recommend checking out a Prism sight for shooters with astigmatism.
Parallax Performance
A parallax free reflex sight is something companies often market to the users, but...
Remember that, in fact, no no optic is 100% completely parallax free
Generally the parallax shift in a reflex sight is more noticeable when aiming at a target close up, and there is no better way to explain this than to show you below:
Battery Life
The battery compartment holds a CR2032 battery that lasts about 50,000 hours, plus a solar panel that acts like a fiber optic under daylight settings to dual power the sight in the event the battery dies. So, apart from long battery life, you can always have a backup!
The solar panel will immediately power the reticle without a battery, but if it doesn't detect light or under the shade, it will turn off and requires a button press to reactivate it when the light returns.
Construction
The construction of the Holosun 510C is rock solid.
You can view as many images online as possible, but once you hold this red dot sight in your hands, you will very quickly realize this thing is well made.
Check out other high end optics for CZ Scorpion
This is an open-reflex sight like the RMR without a protected lens on the back. The only downside of this design is that things can get inside the optic and fog up a clear lens or the emitter, which leads to reticle malfunctions.
Note: this is definitely NOT a Sightmark clone.
Mount
The Holosun 510C comes with a quick release mount for fast optic attachment and detachment.
The part we like the most is the ability to lock the throw lever and the ability to tighten the screw for a rock-solid mount in order to hold zero and prevent the optic from falling off the rifle. At the same time, thanks to a quick detach system, you can easily take this red dot sight off whenever you don't need it.
The mount comes with the optic as one piece construction, and it sits just at 1/3 co-witness height, which works for most shooter on most long gun platforms.
If the shooter feels the optic mount height is short, please use a mount riser to lift the optic up for a better sight picture.
Windage and Elevation Adjustments
The Holosun 510C features 0.5 MOA/click elevation and windage adjustment knobs, and both knobs can be easily adjusted with the tool provided in the packaging or use a small flathead screwdriver.
However, the problem comes when you don't have a small flathead screwdriver or the tool with you in the field to adjust the red dot sight.
It is unlike Aimpoint and other red dot sights, where users can adjust the knob with a penny or a shell casing.
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Shake Awake
This red dot sight offers you three Shake Awake timers - for 10 minutes, 1 hour, or 12 hours, helping you to preserve the battery life if you are not in auto mode. However, if you don't like this feature and don't want to wake your device up every time you need to use it, you can easily turn Shake Awake off.
To turn off this red dot sight manually before putting it into storage, you need to hold down the + and - signs at the same time for 10 seconds.
Easy Usage
One of the significant reasons to choose this optic from all the available reflex sights on the market is that it is really easy to use, even though it has a lot of interesting features. No matter if you are experienced in shooting, or you have just started your adventure with it, you are not likely to find any difficulties in operating this red dot sight.
One of the features making the use more convenient is placing all the controls and the battery compartment on the sides. It means that there are no controls on the rear except for the elevation options at the top, so you can easily access the magnifier behind without blocking your ability to reach the buttons.
Final Verdict
If you're looking for other high-quality reflex sights for a spare rifle lying around the house, the Holosun 510C is the best large window optic to buy.
If you want something that is more duty proof. The Holosun 510C may not be the ultimate choice until you save up for something like the Aimpoint Micro, EOtech or Holosun 515.
It's by far the best red dots under $310, for a few reasons mentioned in the review above. It's also the best option for anyone starting out as a new gun owner because it's rock solid, and it has better features (including multiple reticles, an integrated solar failsafe panel, and long battery life) than anything we had before without burning a hole in your wallet!
Vendor | Price | Sale Price | Status |
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Pros
- Rock solid construction
- Very unique look
- QD mount lever with locking feature & adjustable tension screw
- Multi-reticle system for various shooting applications
- The battery-saving Shake Awake feature
- Easy use
- Unlimited eye relief
Cons
- Open emitter can attract dirt
FAQ
Can I use night vision settings in this red dot sight?
As a rule of thumb, all the high-end red dots should have a night vision mode available, and this one is not an exception. You just need to pick one of the two dimmest brightness settings and you can efficiently use this optic with a night vision device of your choice.
Is it a holographic sight?
No, this optic is not a holographic sight. It is a reflex sight with an LED providing the aiming point. It can sometimes be confused with holographic sights because it has a reticle that is also frequently used in these optics.
Can I switch between a green and red dot in this Holosun optic?
You can buy these Holosun optics with either a little red dot or a green one. Keep in mind you must choose one before you make your purchase because there is no possibility to switch between the two colors in one device.
What firearms can I use with this red dot sight?
The Holosun HS510c can be mounted on any firearm with a Picatinny rail. It is often recommended for AR-15 rifles, but you can also use it with various shotguns, pistol-caliber carbines, or other guns that have full-size 1913 Picatinny rails.