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Holosun HS403B Micro Red Dot Sight Review

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We are always on the lookout for the most affordable and feature-rich red dot sights in the market. We’ve tried many, and while most of them have impressed us, some stinky ones come across. From our experience, there is a fine line between having many features and becoming an obstruction when it comes to red dot sights. There has to be a balance between feature and convenience. So we got our hands on the Holosun HS403B Micro Red Dot Sight and tested it to find all the great things and the not-so-great things about it.

Build Quality of Holosun HS403B Micro Red Dot Sight

Build Quality of Holosun HS403B Micro Red Dot Sight
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Whenever price is the biggest selling factor of any scope, we kind of prepare ourselves to see poor build quality, both in fit and finish and the materials used. But that’s not the case with the Holosun HS403B. The Body is made of T6 aluminum (which is a hardened alloy version of aluminum) along with layers of oxidized coating on top. It makes the scope feel light but dense and solid. So add it to your Ruger or Smith & Wesson, and you won’t notice much difference in the scope and gun quality.

The frosted aluminum finish in black color adds to the quality and looks of this scope. Additionally, the placement of buttons and the shape of the scope make it very ergonomic. The bottom line is; that this scope does not feel out of place whenever mounted on any gun, be it a rifle, shotgun, or your dandy handgun.

Features of Holosun HS403B Micro Red Dot Sight

Features of Holosun HS403B Micro Red Dot Sight
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Now, let’s come to the most important bit; features. The Holosun is priced low, but does it run low on features? Not exactly. It’s a simple red dot sight, and while it does not do many things, whatever it does, it does well. So let’s start with the reticle.

1. Reticle and Viewing

The reticle in the Holosun HS403B is a bright red dot. It comes with a 12 brightness level setting, making it very easy to use directly under the sun and at pitch-black night. The red dot comes with 2 MOA, which is the industry standard, but if you have astigmatism (which makes dots look like a smudge or blur), this might not be a great scope for you.

2. Objective Lens

Objective lens
Image Credit: https://www.reddit.com/

The glass quality is equally great. It is very clear with 20mm of lens diameter, with minimal chromatic aberrations. The glass is coated multiple times to improve the light transmission with minimum distortion. The view field is great with little to no environmental blocking, even while firing the rounds. A big concern while testing the scope was parallax because we have tested many low-priced scopes that suffer from it. The HS403B comes with a parallax-free glass.

There is also 1x magnification which means that it won’t be of much help when it comes to aiming for targets at a distance, but that is understandable. The HS403B is a simple but powerful red dot sight, and that’s it. Nothing too much, but good at whatever it does.

3. Extra Features

The basics are dealt with, but does the Holosun HS403B come with extra bells and whistles? The most important added feature that we loved was the Shake Awake feature which turns on the scope when the gun is given a gentle shake. This feature comes in handy in saving battery life.

The scope comes with two top-mounted buttons to adjust the brightness. The MOA adjustment can be made using a knob that is also placed on the top. It comes with 0.5 MOA adjustments which are decent. The quality of the button and the knob is great. However, the knob size felt a little too small, and some people might have a tough time adjusting the elevation and windage. 

4. Battery Life

The battery life of the HS403B, is outstanding, so much so that we could not test it completely. That’s because it comes with a claimed battery life of 50,000 hours! Little calculations, and it comes out to be over five years! We doubt that it would last over five years, but we are sure that it can easily stretch to over four years. The good thing is that it works with a normal CR2032 lithium coin battery which is easily available.

Our Review for Holosun HS403B Micro Red Dot Sight

Using the Holosun HS403B was a delightful experience, especially because we were not expecting such great performance at such a low price. In addition, the scope comes with two mounting options, both standard and low-profile mounting. The scope fit on the gun firmly, and we fired a few rounds in the range. 

The scope gave great visibility and a field of view, and the red dot was very accurate in aiming, with a few MOA fixes. That’s the great thing we loved about this red dot sight; it’s simple and powerful, with no excess, no mess. The HS403B is also very manageable, with dimensions of 2.45×1.43×1.7 inches and weighing only 2.82 ounces. The presence of unlimited eye relief makes it so convenient to use.

We faced no issues with this scope; the glass was clear, and the red dot worked perfectly fine. It is a great red dot scope, and it’s a steal for the price it comes at! While it is very hard to describe all the great things about this scope, and you’ll have to use it for yourself to know it, here’s a summarized section of all the pros and cons of the Holosun HS403B.

Bonus Read: Holosun 510C: A Budget Friendly Red Dot {Complete Review}

Shake AwakeYes
Battery Life

100K Hours Claimed (at setting 1)

Reticle Red/Green dot
Water & Dust ProofIP67
Windage & Elevation Range+/- 50 MOA

Pros and Cons of Holosun HS403B

These are the things loved about the Holosun HS403B and some things that we did not like. Since the number of things we liked is more than the dislikes, we are happy to recommend this product to you.


  • Great Battery Life
  • Excellent Price 
  • Great W&E Range
  • High Build-Quality
  • Water and Dust Proof
  • Great Objective Lens Quality
  • Red/Green Dot Availability
  • Rubber Cover & Lens Cloth Included


  • Lack of a Carry Case
  • No Fog-Proofing in Objective Lens
  • Lifetime Warranty only for Body


As you can see, we can put the shortcomings of this scope under the “nitpicking section,” and honestly, that’s done just to add a cons section. However, if we think about it, for the price of around $200 (it fluctuates, you can buy it for as low as $195), the price to feature ratio is excellent, and we can easily neglect the cons here. Our verdict? The Holosun HS403B is worth every penny, and if you are looking for a low-cost and great red dot sight, there’s no better option than the HS403B.

About Author

James Towndrow, a NRA-certified Firearms Instructor. During a career of 18 years had won several shooting competition including major leagues. Taking all those experience down the road, is now a successful Shooting Instructor in Texas, US.