Holosun Hs403a Review


High functioning optical sights, can take the beating of the basic use, such as being dropped without damaging the lens and can be submerged underwater and still acquire a target accurately. If you are, therefore, wondering whether you should trust your life with the new optical sight that could be daunting as you will have to sample many before you settle with one that is reliable.

It’s been a while since I went out shopping for some new pair of optical sights, but truth be told finding a unit that will hold up for the long haul is difficult, because there isn’t one unit that is perfectly equipped. However, there are a few important features that I prefer to settle with and which must come equipped with the optical sight.

The sights lens coating must, therefore, be good, the dot crisp, and clear complete with various levels of brightness and Night vision settings; the above features are guaranteed to afford me accurate target acquisition whether am shooting from the range or hunting. Given the above features, I narrowed down to the Holosun Hs403a, whose impressive performance will be discussed in the excerpt below.

Holosun Hs403a Review & Breakdown

The best feature of the Holosun Hs403a that most shooters like is the fact that it enables situational awareness, and users can, therefore, aim with both their eyes open. The unit has incorporated a couple of innovative technologies that encourage ease of use and helps improve functionality. One of the optical sights outstanding features is the “auto wake,” which activates the sight when vibration is detected.

The sight is parallax free meaning that users can expect to achieve an accurate shot even when they are positioned awkwardly or when they move their head away from the lens. For the above, however, they must ensure that the sight remains fixed on the target. Equipped with a durable battery, the Holosun Hs403 will offer you about 50,000 battery life, which in other terms totals to approximately 5 years of continuous use.

And apart from the motion wake feature, the sight has been equipped with an intelligent auto shut off feature, which will automatically put the sight off after staying idle for up to eight hours. What’s more is that the incorporated objective lens diameter is large and users can, therefore, expect to be provided with a wide field of view, apart from that the front lens, is angled purposely to help prevent glare.

Now glare, as understood in the optical sights landscape is the perceived loss of visual performance, caused by intense light coming from the field of view, and which is greater than the intensity of light that the human eye is adapted to. The above then means that if your optical sights are not glare-proof then target acquisition is a pipe dream, given the simple fact that your eyes are barely able to manage too much glare.

What we liked;

  • Equipped with an auto shut off feature that goes off after 8 hours
  • Also comes with the auto awake vibration feature
  • Front lens design helps to prevent glare
  • Large objective lens diameter offers a wide field of view
  • The construction is durable and reliable

 What we didn’t Like;

  • Short battery life
  • The sight has a problem holding zero
  • The dot is not stable during shooting
  • The sight does not offer the 40 clicks maximum as stated

Holosun Hs403a Specifications

Holosun Hs403a
Scope sight
With mount 76g

With low profile mount 94g

Working temperature
-30° to 60°C
Storage temperature
-40° to 70°C
Levels of brightness settings
Up to 3 brightness settings (1, 2, 3), 4 to 12 are the day time settings,
Red dot size
Auto shut off
8 hours
4.3 ounces

Holosun Hs403a Features

Design and Structure

Out of the box, the Holosun Hs403a comes equipped with a low mount, two Allen keys, a coin like battery, and screws for attaching the mount. Sporting a dark black matte finish the sight is quite sturdy made of the durable aluminum. At the back and the front, you have been provided with the rubber protection caps to keep the lens safe when not in use or during transport.

At the top part you have been provided with the easy to reach power and brightness adjustment knobs, what’s more, is that the windage and elevation dials have been strategically positioned on top and on the right side. Now a rather disconcerting feature is the battery mount, which goes in between the sight and the mount, well the above can be quite hectic when it comes to replacement because you have to take your time and unscrew the mount by the footballs.

So while the above can seem like a hurdle, it is actually for the best because it eliminates bulk, and allows shooters an expansive natural field of view. Operating the sight is pretty easy as all you have to do is press both the negative and positive buttons located at the top of the unit. Remember also that this unit has been equipped with the intelligent on and off feature.

Brightness settings and performance

The Holosun Hs403a is a high-performance sight equipped with the latest technology for ease in operability and functionality. So upon 8 hours of inactivity, the sight will go off and you can also get the sight up and running when vibration is felt around the vicinity.  Dot intensity can be adjusted using the provided positive and negative buttons incorporated at the top, so for the low light situations, you can reduce the dot intensity by pressing the negative button at the top part of the sight.

And if you want to use the sight in the bright light situations then the positive button at the top of the sight will increase the dot intensity to complement your environment. The sight is parallax free, so when zeroed in, you can expect the point of aim to be the point of impact. The red dot sight can be used under all types of weather conditions and retails at a fair price. The unit handles recoil quite well and will, therefore, remain stable during use.

Objective Lens diameter

Enthusiasts proclaim that the bigger the diameter of your optical sight, the better the view, which is true, a bigger objective lens, admits in more light which in return renders high resolution and clear images. What’s more, a larger objective lens provides a wider field of view, when compared to a smaller objective lens. On the downside, however, is that this objective lens could be heavier on your gun.

The above then means that you might experience minimal delays when it comes to dot recovery, the extra weight might affect quick transitioning from one target to another. However, some of the enthusiasts don’t mind the extra weight as they believe that it helps with recoil.

Waterproofing and submersion

Professional sights need to be submersible to about 100ft, to which end the Holosun Hs403a will greatly suffice, as it can be used underwater for a depth of 100ft without compromising the integrity of the dot and without becoming foggy.

The unit can be used in areas with a lot of moisture, and with the minimal adjustable features, debris, dirt, and water are restricted from penetrating the sight.

Brightness settings

For optimal performance, an optical sight must come equipped with varying levels of brightness and night vision settings. The above makes the sight usable in different lighting situations for example, when the sun is glowing too bright, you should be able to tweak the brightness settings to overpower that of the sun consequently providing you with target in sight.

Also if you are to use the sight at night the night vision levels of brightness settings should enable you to acquire your target effortlessly and to make it even better it should be parallax free. All the above features can be found in the Holosun Hs403a, the unit is parallax free with various levels of brightness and night vision levels.

Who is it best suited for?

The Holosun Hs403 optical sight is very versatile and can, therefore, be used in long-range shooting; it is a good hunting sight and doubles up as a professional unit.

Are there any alternatives to the Holosun Hs403a?

Features of the Alternative optical sights

Aimpoint PRO Red Dot Reflex Sight
Aimpoint 12417 Micro T-1 2 MOA
EOTECH 512 Holographic Weapon Sight
Night vision compatibility
3m deep
Brightness settings
6 brightness settings, 4 night vision
13 brightness settings ( 4 night vision settings, 8 daylight settings
6.75 x 4.63 x 3.38 inches
5.6” x 2” x 2.5”
68 MOA ring, & 1 MOA dot reticle
Objective lens Diameter

Final Verdict; so, should you get the Holosun Hs403A

Yes, the Holosun Hs403a boasts of a super long battery life, which their red dots can maintain, the sight is submersible up to 100ft and is parallax free meaning that target acquisition isn’t a problem. The unit is highly effective with the automatic on and off feature that protects the battery and varying brightness levels ensures that you get the relevant dot intensity either in low or bright light situations.


  1. Must I use the Torx screw to mount the Holosun Hs403?

The Torx wrench hardware offers more torque when compared to the normal hex Allen wrench, which ensures that the sight is mounted as robustly as it possibly can.

  1. What is the threshold of the Holosun Hs403 when it comes to recoil?

In reference to bench testing the sight offers 1000g.

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Terrence Miller
Terrence Miller is a hunter by birth, picking it up from a lineage of hunters and will probably hand the skill down to his son. He has been hunting since he was a young boy and has knowledge of both the new and old hunting equipment. This goes to say that the information provided is very reliable and conclusive. Using the hunting rifles and getting the right hunting gear seems to be a challenge for many individuals who want to learn the skill of hunting. And the reason why the information presented by Miller has detailed coverage on the different types of rifles, and rifle scopes. When not in the wild hunting, Miller loves horseback riding.


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