Holosun HS503GU vs Vortex Sparc AR

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This time, we are going to analyze two red dots, that are, at the moment, some of the lightest, most compact tubular sights out there at an amazing price. Both are full of features, technologically advanced, all packed into compact and sturdy packages. We will be comparing the Holosun HS503GU and Vortex Sparc AR sights. Beside the fact that the Holosun has the multi-reticle ability, they are very comparable and, in a way, quite similar.

Size, weight, and looks


Two optics, both very light and neatly compact – can be used on any rifle, SMG, conversion and much more, without taking up much of the rail space. Even the knobs on the two devices are nicely tucked away and do not stick out – they do not obscure vision and are not opened to danger of getting knocked off or snared into any other piece of equipment.

Holosun comes in two colors, either black or FDE, is well rounded and just looks good. The Vortex is just a bit bulkier with the rubberized sleeve, but has a bit sharper edges, giving it a nice, aggressive look. Holosun comes packed in a plastic box with a foam inlay for the optic as well as the attached mounts, a high and a low one, the rubber lens covers and the battery. The Vortex also comes in a nice and sturdy cardboard box, with a custom foam inlay that hosts the device, both mounts (high and low) and the battery.

With different height mounts that come with both optics, attached batteries, whichever you choose, it comes packed so that everything is included and the user can be range ready in no time.


Holosun HS503GU

Vortex Sparc AR


178 g

213 g


30 mm (without mount)

59 mm


62 mm

73.5 mm


37 mm

42 mm


Standard Picatinny mount

Standard Picatinny mount

Vortex Sparc AR (on the left) and Holosun HS503GU (on the right)
Vortex Sparc AR (on the left) and Holosun HS503GU (on the right)


General properties

The Holosun comes equipped with a wide variety of great features. Some, such as the reticle, are discussed below, but there are some that need to be pointed out here. The sight is not only compact but also resilient. The manufacturer claims it can take some punishment as it is both shock and water resistant, and it does feel that way in your hand, with the only thing that might take any damage being the black or FDE finish that comes with it. With a standard CR2032 battery, it has an incredible working span of up to 50.000 hours at the lowest settings, which still gives you hundreds of hours if you use it at the highest brightness at all times. That being said, a battery will probably outlive the warranty on the sight, set at an acceptable 3 years for electronics and 5 years for the lenses and housing.

But that is not all, the HS503GU comes with some neat features. It has a multiple reticle system (the MRU), which is quite rare in red dot sights, and we shall discuss it in detail below. It also comes with the Shake Awake function. It means that the optic has an auto power off feature and will turn off when it is stationary for a while. It will also automatically switch back on at the last brightness setting when it detects shaking and vibration – namely, when you grab your rifle and want to use it. It, therefore, saves battery life but is available at moment’s notice when you really need it, without the use of any buttons.

Several options are possible for this sight as well – the one we had for our review is the one with the U designation, which means that the windage and elevation knobs are protected by an elevated part of the housing on two sides. It can also come in the C configuration, which has a solar cell on top, for back-up power supply.

The Vortex does not have such specific functions and features, but is still an impressive little device. The best part is the fact that Vortex offers their ‘lifetime’ warranty on their optics, meaning that should something ever go wrong, they will fix or replace your sight in most cases. Not that anything should go wrong, as the optic is really rugged, coated with a protective rubber coating for additional protection, and is highly resistant to shock and water.

The battery life is not as good as with the Holosun, which is just insane, but a single AAA battery will feed the Vortex for about 5000 hours at the lowest setting, or a good 300 at the highest, which is more than an acceptable timeframe. The high-grade lenses with advanced coatings will eliminate any glare and provide a great view at all times. They are placed in a way to have near unlimited eye-relief for ease of use.

The only thing that really bothers with the otherwise great Vortex are the lens caps. They are not removable and are a part of the rubber shroud that encases the whole device. That is good in a way, as you can’t lose them. But when you open them, they hang so that they are in the way. Supposedly, they are made in a way so that they can be stuck together on the side of the optic and stay there, but at least in the sample we got, that doesn’t really work and they refuse to stick together.

So, to quickly sum up. At the price you pay for them, these two devices are simply incredible and will hold their ground even against much more expensive optics. Compact, reliable and with a nice view, they will serve any use and in any circumstances. Loaded with great features, they are well worth the price, and more!



Holosun HS503GU

Vortex Sparc AR


289 €

299 €

Producer (country)

Holosun, USA (CA)

Vortex, USA (WI)


-3 years (LED, electronics)

-5 years (lenses)

-Unlimited Lifetime Warranty

Battery type



Battery life

50.000 hours (low setting)

5000 hours (low setting)

Water resistant

Yes (IP67)


Shock resistant



Operating temperature

-30 to 60 C

-20 to 70 C

Vortex Sparc AR (on the left) and Holosun HS503GU (on the right)

Optical Properties


The Sparc AR bears the signature of all Vertex optics, that being great, quality lenses with their advanced coatings. This results in a very clear, sharp image, not too tinted so it offers a bright view. The coatings prevent most of the glare even in direct sunlight and will protect the lenses from stains and even minor scratches.

Holosun does not lag behind it though, with good glass that provides a clear and bright image in most conditions. Its coating reduces glare and reflection just as well, and both devices should be placed on the top of the scoring ladder when it comes to lenses.

Both sights have a small lens but that is expected of compact red-dots. Nevertheless, they offer a wide enough view for most applications. Both offer zero parallax (as much as that is possible), a virtually unlimited eye relief, more than enough brightness settings and the possibility of using them with night vision goggles.

The HS503 has a good adjustment range of 50 MOA in both windage and elevation, but Vortex really shines here with 90 MOA adjustment range. Holosun offers smaller clicks of 0.5 MOA for really fine adjustment, but the 1 MOA of the Sparc will do the job just as well.


Holosun HS503GU

Vortex Sparc AR

Lens diameter/size

20 mm

22 mm







Eye relief



Click value

0.5 MOA


Adjustment range

50 MOA

90 MOA

Dot size

-2 MOA (dot)

-65 MOA (reticle)


Adjustable brightness



Brightness settings



NVD compatible



Vortex Sparc AR on the range
Holosun HS503GU on the range




Both dots are really good. They are actually impressive considering we have seen dots on higher settings turn into blobs at devices that cost several times more than these two. It has become almost a statement for Holosun that their dots are extraordinarily good, and the dot on the HS503 is just a bit better then on the Sparc, it is not just good, it is perfect.

The two devices come out equal in the size at 2 MOA dots, which is nice and fine for any use, but the HS503 offers an advanced option here, the use of a 65 MOA dotted reticle that is discussed a bit below. The reticle is a simple segmented circle of 65 MOA with a 2 MOA dot in the middle and can easily be turned on or off.

In the pictures, the dot isn’t crisp because the camera didn’t focus the dot, but only the device itself. 

Vortex Sparc AR
Holosun HS503GU




As always, we just had to take the sights to the range. We always test them with different calibers to check how they handle the shock and stress and if the dot moves at all, or anything starts rattling. It needs to be said, both performed admirably in rifles, a 9×19 conversion kit as well as a shotgun that has the most potential to loosen up something. The dot remained zeroed. The mounting is not the fastest out there but a standard Picatinny mount that requires a key to fasten, once mounted, it will not move at all.

When it comes to zeroing, both the HS503 and the Sparc come with small and capped, as well as protected (with elevated protrusions from the body) dials, so it is not the easiest way to make fast corrections, but then again, it is not made for that. It is made to be zeroed and then used and abused and made in the way that the dials are virtually untouchable, so the sight remains accurate.

The shooting itself is made easy as both offer a nice and fine dot, a clear and sharp image and a wide enough field of view. But it was in the practical part where the Sparc ran into a few little problems. First, the buttons for brightness adjustments are in a bad spot. They are right in front of your face, which some might claim is good, but then again, you don’t need to see the buttons, but you orientate yourself by looking at the dot, and where they are placed is just not handy, especially on smaller weapons platforms, or when wearing gloves, as it is simply hard to reach (Holosun has the buttons on top and they are handy to use). Secondly, the awkward lens caps that we mentioned before, that just keep falling apart when you fasten them together on the side, and then keep being in the way.

It turned out that the reticle of the HS503 is very useful. It does not offer a BDC system or anything like that, but it is a way to get yourself on target quickly, especially on closer targets. If it is in the circle, it will be hit, and the circle is much faster to spot and put on target than a small dot, especially in very bright conditions. 

Vortex Sparc AR on a semi-auto 12 Gauge
Vortex Sparc AR and Holosun HS503GU mounted on the weapons
Holosun HS503GU on an AR chambered in .223 Rem.



Besides a few tiny annoyances with the Sparc, there really are no complaints with these two devices. They offer incredible value for the low price with good glass, sharp dots and great features. In their range, they reign, and they can easily be put side by side with many high priced, well-known devices. It is due to this that both mentioned companies take a large share of the market with growing sales. They offer superb products at reasonable prices and top it off with a fair approach to their customers and are therefore rapidly becoming some of the most recognizable names in the business right now.




We would like to thank Optics Trade for letting us use and test the above-mentioned products. We also thank them for letting us use their videos.

This featured test is impartial and we always try our best not to prejudice and favor one product over the other. Our team of enthusiasts who tests these products and writes these articles is doing it from dedication, as rifle scopes are our big passion. We also feel a great amount of joy and satisfaction when we know that we have contributed and shared with you our experiences. We try not to be biased and try to be as accurate as possible when interpreting our sightings. We will do our best to described things as they really are.

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