HANDS ON: Holosun HS403B Review (2 MOA Red Dot Sight)


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Holosun has attracted an enormous amount of attention over the years for quality performance and affordability.

I have a positive opinion of the brand given that I own (and field-tested!) the HS510C. But the HS403B is about half the price.

In the realm of affordable red dot sights, how is it different?

Field testing the Holosun HS403B red dot sight

The Holosun HS403B is a quality red dot sight that qualifies as a budget optic for law enforcement, hunting, and home defense. The Shake Awake technology makes it a long-lasting, instantly ready optic for immediate engagement and is why it’s a red dot that stands above alternatives.

Given that it’s literally one of very few that has the motion sensor feature for under $150, it is definitely worthy of our attention.

Target Tamers bought the Holosun HS403B and I gave it a hands-on test to see if it has value or if shortcuts were taken in trade for the Shake Awake.

Quick Overview...

What We Like: Shake Awake

What We Don’t Like: Battery tray compartment

Best Uses: CQB, Close to Mid-Range, Hunting, Tactical, Small Caliber Rifles, Heavy Recoil, Shake Awake

  • Magnification: 1X
  • Coatings: FMC
  • Eye Relief: Unlimited
  • Reticle: 2 MOA dot
  • Adjustments: 0.5 MOA
  • Battery Life: 50,000+ hrs
  • Dimensions: 2.45 x 1.43 x 1.6” / 2.82 oz
  • Mount: Low profile & Lower 1/3 co-witness

Our Verdict: The quality Holosun HS403B comes with everything red dot sights are expected to have these days. It goes a step further with adjustable Shake Awake that is rarely seen in this price range. This expands its potential for use in multiple applications increasing its value and desirability.

Who is the Holosun HS403B 2 MOA Dot Best Suited to?

Overall, the Holosun HS403B is a red dot sight best suited to shooters on a budget. It’s the exemplar of value as it offers more than a few features that are not always present in affordable sights.

Additionally, the Holosun 403B will attract the eye for its most beckoning feature, Shake Awake. This is what makes it a potential RDS for law enforcement on their patrol/duty weapons. It’s also a valued feature for home defense and SHTF rifles.

As a top budget red dot sight, it stands apart from the pack for this very feature.

YouTube video
See how the Holosun compares to 6 other budget red dot sights in the video above!

How Does the Holosun HS403B Perform?

Overall, the Holosun HS403B will perform exactly as expected with its 2 MOA dot, 12 illumination settings, and Shake Awake technology. It’s performance in the field confirms the motion sensor is reliable, the build quality is impenetrable, and its button operation is effortless.

Button operation of the Holosun HS403B
Button Operation of the Holosun HS403B

In my hands-on field testing of the HS403B, Shake Awake was at the top of my list to test. Because I’m impatient, I kept checking to see if it had turned off every 60 minutes. Shame. I failed to read the manual. I also failed to read the manual about battery installation – but more on that later.

Accessories and instruction manual included in box with Holosun HS403B
Included accessories and instruction manual (tip- read these!)

Long story short, the dot turned off after eight hours. I have had literally no issues with Shake Awake over my duration of ownership. It’s like you forget it hasn’t been on the entire time it’s not been in use. That’s how it’s supposed to be right? By the time I bring the rifle up, the dot is there – ready for work.

I generally despise button operation on a RDS especially with gloves on. Yes, they provide a sleek, slim look, unobstructed view, and make for easy, ambidextrous on/off and illumination operation convenient.

However, feeling them beneath gloves is tough and I never know exactly what setting I’m on. I suppose that should be a psychological benefit – adjust for ambient conditions rather than obsessive attention to the number. I still like the knob better, and I feel like I take a little longer to find the buttons and then make sure I’m on the right one. I’m just not a button person.

Besides personal preferences getting in way, the Holosun 403B performed excellently for what I deem is a value buy. I thought there would be some quality compromise in trade for the Shake Awake, but it’s proven to be a solid RDS through and through.

Features & Benefits

Shake Awake

Holosun HS403B red dot on patrol car

The Holosun HS403 is one of the only red dot sights in the market under $150 with Shake Awake technology. It senses motion and will activate the red dot instantaneously before the rifle is positioned for shooting. After a period of time of non-motion, the sight will enter Sleep Mode.

Checking hiding spots LEFT Around a corner RIGHT Dumpster
Checking Hiding Spots: Around a corner (left), near a dumpster (right)

This is a feature many in the tactical professions will appreciate. That not only their rifles are loaded and ready, but their optics are too. LEOs, security personnel, and even armed civilians choosing to make personal defense a priority will gravitate towards Shake Awake technology.

LEFT Truck thru brush RIGHT Checking over walls
Covert Use: Monitoring truck through brush (left), checking over walls (right)

As the default setting, the sight enters sleep mode after 8 hours of no movement. It’s adjustable from 0-12 hours. This is the one saving grace of the Shake Awake tech that hunters may forgive. Having an adjustable, continuous-on period will be beneficial for hunters so that it doesn’t turn off in the moment they need it most.

LEFT Egret 113 yards RIGHT Dot is on crow in tree
Monitoring Wildlife: Egret @ 113 yrds (left), Crow in tree (right)

There’s a bunch of well written instructions on adjusting the sleep mode timer. It’s tedious for me to be honest. More power to you if you want to change the default timer and go through the button clicking to do it.

Turret Quality

Overall, the Holosun HS403B has very tactile and audible 0.5 MOA turrets that track accurately. The caps serve as the adjustment tool though another multi-tool is included in the box for this convenience.

Turrets on the HS403B red dot

A small detail that I appreciated is that the turrets caps themselves are not recessed into the body, so it’s easier to grab and twist off. I could hear the clicks over ear protection at the range.

Though they are not referenced with arrows or letters to indicate UP and R (anti-clockwise), it’s safe to assume standard operation. Yes – the instructions also confirm this, albeit I didn’t read them until after the fact.

Zeroing the Holosun HS403B
Zeroing the Holosun HS403B

I got on paper with the first 3-shot group. From there, zeroing in with an AR-15 was routine all the way out to 100 yards. But unloading a magazine on a full silhouette target at rapid speed was exciting!

Paper Target 50 yards Unloaded 25 round 556 magazine rapid fire through Holosun 5X403B
Paper target @ 50 yards - Unloaded a 25 round .556 magazine rapid fire

Build Quality

The extremely lightweight build of the Holosun RDS is noticeable. At 2.82 oz, it’s legitimately nothing to add to an AR-15. It should be slimmer than most other red dots, given that it lacks a knob for the battery and illumination controls, but any bulk shaving benefits are close to negligible.

Waterproof testing the Holosun HS403B red dot

In general, the HS403B is IP67 rated – so it’s both dustproof and waterproof. It’s the middle of Monsoon season and I saw a good opportunity to get the Holosun wet. It’s not uncommon to be exposed to the elements when in the hunt and gear gets soaked. With that line of thought, the 403B got left outside in a downpour.

Holosun HS403B with Wet eyepiece RIGHT Wet objective lens
Wet eyepiece (left), wet objective lens (right)

I was planning on retrieving it after 30 minutes, but I forgot. 60 minutes later, I saved it from further exposure. Beaded water was everywhere, and it also got into every nook and cranny of the mount. The dot was still going strong and another while later, it looks as good as it was out of the box.

Holosun HS403B Inside of mount is wet but dot still working and visible
Moisture everywhere including inside of mount (left) but the red dot is still going strong (right)

There are no left-over water spots inside the tube and no internal fogging, though there are a few hard spots of dried water drops that I gently cleaned off with a microfiber cloth.

The Holosun HS403B is made in China

The Holosun RDS is made in China, manufactured from 6061 T6 aluminum, and it sports a MAO (Microarc Oxidation) finish. I tend to instigate scratches and a lot of accidental abuse, but the finish has held up impressively well. Another budget dot sight that I field tested cannot say the same.

Illumination

Illumination on the Holosun HS403B is provided via a CR2032 battery rated to last 50,000 hours when used at setting 6. It has 12 illumination intensities in total with 10 being daylight bright and two dedicated for use with night vision devices.

It’s absolutely daylight bright and easy to pick up against various backgrounds and targets. It struggles to remain visible against reflective white surfaces (as do most sights), but with focus, it can be seen.

As seems to be the trend with reflex sights, I liked to sit in the higher intensities mostly at max brightness while mobile and in urban environments. While you’re using it, you don’t any notice reflections. At the shooting range in the desert, setting 8 was great to minimize dot flare against tiny 1” square targets.

1x Left 3x Right with Juliet 3x Target at 34 yards
Target @ 34 yrds: 1x magnification with red dot (left), 3x with Juliet3 magnifier (right)

Settings 1-4 are invisible for me but are extremely appropriate for low light and dark conditions. NV settings 1 and 2 are designed for visibility through NVDs.

As a side note, I felt forced to wear my prescription glasses with the HS403B. I was seeing the dot differently and decreasing illumination did not alleviate dot distortion, but my glasses corrected for it. There are few dot sights I’ve had to do this with and the Holosun is now another.

Mounting

In general, red dot sights come with a mount. While the expectation is now being set to include a multi-height mounting system, cheap sights don't always follow this trend. Fortunately, Holosun satisfies the demand and includes a low-profile mount and a high riser mount for a lower 1/3 co-witness.

Included Riser mount and low profile mount for Holosun HS403B
Included riser mount and low profile mount

I ran the HS403B with MBUS sights – no problem there. The low-profile mount is great for my Ruger 10/22 but also for shotguns and AK platforms. The sight comes preinstalled to the high-rise mount.

Mounting the Holosun HS403B Lower third cowitness LEFT Thru front sight RIGHT Thru front and rear sights
Lower 1/3 co-witness: Through front sight (left), through front and rear sights (right)

The riser mount fits to Pic rails and has a 1.63” height from the top of the rail to the center of the FOV - presumably where the dot is.

Since it has a T1 footprint, it’s compatible with like mounts if you prefer an absolute co-witness (need a height of 1.41”) or if you would rather have a quick detach mount.

Limitations

Battery Tray Compartment

The HS403B red dot sight has a battery tray held secure via two tiny screws. It takes a CR2032 battery that requires the positive side to be faced down. The tray design ensures consistent connection, side-mounting convenience, and it eliminates the bulk of a knob compartment.

Though it’s just a different battery compartment design, it works, and it shaves off some protruding bulk, I hate it.

HS403B Battery tray compartment with tiny screws
Tiny screws on the battery compartment

The mini screws are tedious to deal with. It took me longer than I think is necessary. Do not lose the multi-tool because it’s designated for these screws (I think it’s a T5 Torx size). Obviously, the T10 Torx wrench for the mount will not fit these screws.

Tools and low profile mount included with the HS403B
Battery tray, included tools and low profile mount

I also just assumed the battery was supposed to be installed positive side up, and lo and behold, the Holosun wouldn’t work. Lesson learned – don’t assume. Read the instructions. The booklet clearly says, “POSITIVE side down!”

Popular Questions

What is the Difference Between Holosun 403B VS 403A?

The Holosun HS403A is an archived (discontinued) red dot sight. The primary differences of the 403A were the battery compartment on the base of the body and three NV compatible intensities. Th 403B has a battery compartment tray on the right side of the body and has two NV compatible intensities.

Does the Holosun HS403B Save the Last Settings Used?

The Holosun RDS (403B) has a memory function that saves the last settings used regardless of if it was deactivated due to sleep mode or if it was manually powered down. Upon activation, either manual or motion sensor, it will return to the last settings previously used.

Will the HS403B Red Dot Sight Fit Aimpoint T1 Mounts?

Many want to know if the Holosun HS403B is compatible with Aimpoint T1 style mounts. With the T1 footprint, it is compatible with T1 mounts. Though the 403B comes with low-profile and lower 1/3 co-witness mounts, quick detach or other mounts must be purchased separately.

Does the Holosun HS403B Have Shake Awake?

The Holosun HS403B has Shake Awake technology that allows it to enter sleep mode and reactivate upon sensing motion. The default timer is set for 8 hours but is adjustable between 0-12 hours.

What is the Warranty on the Holosun HS403B?

The Holosun warranty is valid only to the original purchaser and must be registered. For personal use, the frame/housing and glass/optics are warrantied for life. The LED illumination system is warrantied for 10 years from date of manufacture. For LEO and military use, it’s warrantied for 3 years.

Conclusion

After a few fails, through no fault of the optic, I’ve come to appreciate the differences that tripped me up, i.e., adjustable Shake Awake and easy-to-use button operation.

I say this with the exception of the battery compartment. I am not looking forward to losing those screws in the field one day. It also forces you to have the right Torx bit to access it.

Holosun 2 MOA red dot sight

The dot remained highly visible in urban environments and because Shake Awake can be adjusted, it should also appeal to the hunting crowd as a tough, reliable red dot for hog and coyote hunting.

The Holosun HS40B has more to offer than similar red dots in the same price range. Given its performance and value, it’s no doubt a top contender for your shortlist.

Further Reading

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