It is about time we review the Holosun HS403B Micro Red Dot Sight (MRDS). Even though it took us a while to get to it, I think you will be surprised to find how much value there is in one of our favorite budget red dot optics for rifle, carbine, and shotgun applications. This budget-friendly optic has all the necessities and some standard additional technologies you have seen in other Holosun optics.
In the course of this Holosun HS403B review, we outline the specifications along with the features of this wallet-friendly red dot sight. Plus, we will include a comprehensive look at the technologies Holosun has included in this MRDS. Finally, we will cover the pros and cons of the optic and what other shooters have to say about the sight.
Holosun HS403B Micro Red Dot Sight Review
The Holosun 403B is a tube-style micro red dot sight machined from lightweight T6 Aluminum. This optic weighs 4.3 ounces measuring 2.44 (in) x 1.18 (in) x 1.45 (in). Target acquisition is achieved effortlessly through a crystal clear 20mm objective lens and crisp single 2 MOA red dot reticle. The 403B operates on a single CR2032 lithium coin battery providing an estimated 50,000-hour battery life using the mid-brightness setting. Price and quality make the Holosun 403B an excellent red dot sight option for rifle, carbine, and shotgun for the under $200 price range.
Headquartered in Walnut, California, established in 2013, Holosun has since built a reputation for building full-featured red dot optics with innovative technologies. Since its foundation, Holosun has continued to add value often at the request of its customers. Holosun’s 403 line of micro-optical sights consists of several models of budget-friendly options that still incorporate some of the industry’s best features and quality.
Bottom Line Up Front
The Holosun 403B Micro Red Dot Sight carries the same Holosun quality and innovations as its other optics at a budget-friendly price. This optic is suitable for a wide range of applications and is an excellent option at this market price point.
Holosun’s 403 series optics come in several configurations, with the HS403B representing the most straightforward simple design. The optic is easy to put into action with a shallow learning curve. Any skill level of shooter can be putting rounds on target within an hour or two with the HS403B sight.
Top Features of the Holosun HS403B Red Dot Sight
Design
The HS403B is a tube-style red dot sight milled from 6061 T6 Aluminum stock. The use of T6 allows for lightweight yet strong housing. The 403B weighs in at only 4.3 ounces.
This optic is finished with a matte black Micro-arc oxidation (MAO) finish to produce a dense oxide film that protects the aluminum alloy from corrosion attack. Research shows that the MAO technique has demonstrated greater bonding capabilities than many other aluminum surface treatment techniques. This ensures a highly resilient coating that resists scratches and protects the aluminum housing for an extended duration.
From a profile perspective, the Holosun Paralow HS403B is on par with other red dot optics in its class. The sight’s dimensions are 2.44 (in) x 1.18 (in) x 1.45 (in) with a 20mm diameter window size providing a compact red dot sight with more than an adequate field of view necessary for situational awareness and rapid multi-target acquisition situations.
The 403B has an Ingress Protection Code of IP67, which means the unit can be dropped into a body of water up to a meter deep for half an hour. This red dot is also resistant to dust. An IP67 rating makes the optic water-resistant suitable for operation in just about any environment you find yourself.
Reticle
Holosun’s HS403B comes with a red super LED illuminated single 2 MOA dot reticle. The reticle has 12 brightness settings. Ten of those settings are considered daylight settings, with 2 of the settings reserved as night vision compatible.
The range of brightness options ensures that the reticle is observable under various ambient lighting conditions.
Operation
Battery life for the HS403B red dot sight is outstanding. Since this is powering a super LED, you are likely to find a 50,000-hour battery life while operating the optic on the level 6 or 7 brightness setting. This is still a fantastic battery life and will ensure that your red dot sight is ready when you need it.
The Holosun 403B is straightforward to operate. Turning the sight off/on, adjusting brightness, and other available settings are accomplished with two top-mounted buttons.
The Holosun 403 series has a side mount battery tray. To turn on the red dot sight, press and release either button. If you need to adjust the brightness, you simply press the ”+” or ”-” button to the desired intensity. To power the sight off, all you have to do is press both buttons simultaneously.
Holosun Shake Awake
The HS403B includes Holosun’s Shake Awake feature. This motion-sensing technology is on by default when you turn on your optic. You can adjust the sleep delay from 0 to 12 hours of no movement for your red dot sight to enter sleep mode. Once in sleep mode, the sight will instantly wake up and turn to the last setting with the detection of any motion.
This is a great feature that will extend your battery life and keep your sight ready for engagement at all times.
Sighting adjustments are made via a top-mounted elevation adjustment knob and a side-mounted windage knob. Screw-on lids protect both adjustment knobs. The maximum adjustment for both the elevation and windage is +-50 MOA with a 0.5 MOA adjustment per click.
Mounting
The Holosun Paralow HS403B comes with both a low profile mount and a lower 1/3 co-witness mount. These mounts are Picatinny rail compatible and use a crossbolt clamp style mounting system. The clamp screw is adjusted using the provided T10 Torx L-Key wrench.
The low mount is perfect for shotgun applications and carbine setups where no iron sights are present. For your long rifle applications that require occasional use of iron sights, use the lower 1/3 co-witness riser.
Details
Included with your purchase:
- Holosun HS403B Micro Red Dot Sight (MRDS)
- Lower 1/3 Co-witness Mount
- Low Profile Mount
- T10 L Key
- Rubber Cover
- User Manual
- CR2032 Battery
- Lens Cloth
Other Great Features
Holosun uses a multilayer reflective glass manufactured using optical glass with multilayer coatings that reduce glare and facilitate maximum light transmission and wear resistance.
The HS403B has been designed to project its aiming dot to prevent visibility when viewed from the front beyond several meters. This feature reduces shooter signature, which can come in handy under a variety of shooting situations.
This optic comes with the Holosun Limited Lifetime Warranty.
Customer Feedback
The Holosun HS403B has 4.6/5 stars, 82% of the reviews for this optic at five stars, and over 460 ratings.
Easy to install: “Very bright dot, easy to install, easy to adjust, and easy to operate.”
Battery Life: “Battery life is bonkers. The battery life is more than you would expect. No disappointments.”
Value for money: “Buy it — it’s a no brainer! I was totally blown away by the quality of this product and at an unbelievable price point.”
Variations
The Holosun 403 series of optics has several variants:
- HE403B-GR — Green dot, Button operation, No solar
- HS403C — Red dot, Button operation, Solar
- HE403C-GR — Green dot, Button operation, Solar
- HS403R — Red dot, Rotary operation, No solar
- HE403R-GD — Gold dot, Rotary operation, No solar
Alternative Red Dot Sights
If you are looking for an alternative to the Holosun 403, we recommend the Sig Sauer Romeo 5. You will get a similar optic with fewer features and a slightly lower price. Another option at this price point would be the Vortex Crossfire.
