Menu open

Holosun 403B Review – Micro Red Dot Sight Comments Off on Holosun 403B Review – Micro Red Dot Sight

I have purchased my fair share of weapons sights over the years, including, several EOTECH EXPS holographic sights.

Most recently, I was interested in getting a more budget-friendly, but reliable, micro red dot sight for one of my home defense weapons. The Holosun HS403B seemed to be a good fit for my needs.

Why Did I get the Holosun HS403B?

As I stated earlier, I was in the market for an affordable, yet dependable, micro red dot sight. And although Holosun sights are not considered “operator grade”, I have owned several in years past, and found them to be very reliable, have good battery life and hold zero, all for a reasonable price.

In addition to those aforementioned qualities, what I also like about the HS403B is that it has a useful feature called “Shake Awake”.

What is Shake Awake?

Holosun’s Shake Awake Technology turns off the LED whenever its motion sensor detects that it is not in motion after 8 hours (default). The number of hours it takes for the LED to deactivate (to enter Sleep Mode) can be adjusted in 1-hour increments from 0 to 12 hours. Shake Awake can also be completely deactivated.

Features of the Holosun HS403B

  • Red Super LED
  • 50,000 hour battery life
  • Shake Awake technology
  • Last Memory Recall – the sight will remember the last saved brightness setting when powered on and off.
  • Digital push buttons for brightness settings
  • Side-mounted battery tray for the 2032 battery
  • 10 daylight and 2 night vision compatible reticle settings
  • Housing made from 6061 aluminum
  • Waterproof: IP67
  • Parallax free
  • Includes both a lower 1/3 co-witness mount (1.63”) and a low mount (.75”)
  • Includes a rubber lens cover

Holosun offers a limited lifetime warranty.

Holosun HS403B Red Dot Sight
Holosun HS403B Red Dot Sight

How to Adjust the Sleep Timer Delay on the Holosun 403B

  1. Press the “+” button and hold it down for 3 seconds to enter time adjustment mode. The red dot will blink. The number of blinks represents the current time delay. One blink represents 1 hour of time delay, while 8 blinks represent 8 hours of time delay (which is the factory default).
  2. Press the  “+” or “−” button to set the number of hours desired. Pressing “+” or “−” will increase or decrease the time by 1 hour for each press. The LED will blink once to confirm each button press. If the sleep time delay is set to “0” the feature becomes disabled.
  3. When finished, press the “+” button and hold it down for 3 seconds to confirm the new setting and exit the time adjustment mode.

Holosun HS403B Specs

Window Size: 20mm
Dimensions: 2.45” × 1.43” × 1.6”
Weight: 2.82 oz (without mount)

Holosun HS403B Pricing

MSRP is $205.87. I have found it for as low as $118.41 from Lanbo’s Armory.

Holosun 403B Red Dot Sight with Tools
Holosun 403B Red Dot Sight with Tools

General Impressions

Like all other Holosun products, build quality is good. And at 2.82 oz, it is also noticeably lightweight.

Admittedly, I am not a fan of the battery tray as it is held in place by two very small Torx screws. Holosun does include a proprietary tool, that on one end of it, has a Torx to remove the tiny battery tray screws.

At the other end of this tool is a flat head/blade that can be used to pry open the battery tray or adjust the elevation and windage turrets.

The elevation and windage turrets have screw on, protective caps that can be removed and used to adjust those settings as well.

The elevation turret is on the top of the HS403B while the windage turret is on the right side of the HS403B.

What I don’t Like about the Holosun HS403B

As I mentioned earlier, I do not like the battery tray design used in this red dot.

I also do not like the included lower 1/3 co-witness mount (and low mount) because from my experience, Holosun mount cross bolts loosen unless a non-permanent thread locker is applied. This may because Holosun 403B cross bolt is fairly small, especially compared to those found on various aftermarket mounts. The cross bolt head itself requires a T10 Torx (15 in-lbs) but, unlike the AEMS or 510C cross bolt head, is a bit thicker and looks a little deeper, such that it may be less more prone to stripping.

I am also not thrilled that the 403B is made in China, but, all red dot optics in this price range (Vortex Crossfire, Sig Sauer Romeo5, Primary Arms RD-25) are made in China or elsewhere overseas.

Is the Holosun HS403B Compatible with Aimpoint T2 Mounts?

Yes, the Holosun HS403B can be used with any mount designed for an Aimpoint Micro T2 sight, such as the Reptilia 1.93 Dot Mount for Aimpoint Micro.

Holosun 403B and Reptilia 1.93" Mount
Holosun 403B and Reptilia 1.93″ Dot Mount for Aimpoint Micro

Since, I prefer an optical centerline height of 1.93” and wanted a much better quality mount, I attached a Reptilia 1.93 Dot Mount. This particular mount is made for the Aimpoint T2, but is compatible with other micro red dots, such as the Holosun HS403B. The Reptilia mount uses a much larger and more robust cross bolt (T25 Torx, 45 in-lbs) and steel clamp. I was able to pick it up on sale for about $84.

I think Holosun should offer all of their optics without any mounts so that customers can buy a quality mount, like those from Reptilia. You can read my review of the Reptilia Dot Mount for the Holosun AEMS here.

At the Range

That said, having sent about 200 rounds down range, the Holosun HS403B held zero (with the Reptilia mount).

The 2 MOA red dot reticle is as crisp as any other I’ve used.

The glass has a slight bluish tint, but, that has been my experience with all Holosun (and more budget-priced) red dot sights. Obviously, I was not expecting to get the crystal clear glass found on the Aimpoint T2 or EOTECH EXPS3.

Final Thoughts

The Holosun HS403B micro red dot sight is a great option for those looking for a good quality, budget-priced red dot. Shake Awake is one of the most useful features it possesses, not found on some other similarly priced micro red dot sights. And for a street price of less than $125, I think it is one of the best budget red dot sight options available.

Previous ArticleNext Article

Editor Picks