The Holosun HS403R is a compact reflex-type red dot sight, manufactured by Holosun Technologies, designed for semi-automatic rifles and rifles. This model is distinguished by its rotary switch integrating the battery compartment, its 2 MOA red dot reticle and its IP67 waterproofing, all in a lightweight aluminum case weighing barely 100 grams.
History and Development of the Holosun HS403R
Holosun Technologies is an American-Chinese company founded in 2013, with its American headquarters in City of Industry, California. The brand has established itself in the global market of tactical optics by offering sights that combine reliability, lightness and competitive prices compared to traditional references such as Aimpoint and EOTech.
The HS403R belongs to the 403 series, one of Holosun’s entry-level lines for red-dot rifle sights alone. The 403 series offers several variants depending on the features: the HS403B (rear battery, push button), the HS403C (Solar Failsafe solar panel + button), and the HS403R — the subject of this article — which is distinguished by its Rotary Switch. This switch design allows the CR2032 battery housing to be integrated directly into the side adjustment dial, simplifying tool-free battery replacement. The HS403R model was introduced to meet users who prefer intuitive access to brightness settings via a dial rather than a double push button.
The 403 series is particularly successful in the United States, Europe and Asia in the civilian and para-military market, mainly as the main optic on AR-15, AK and M4 type rifles. The HS403R occupies an accessible price segment, generally between 80 and 150 CHF depending on the retailer.
Technical Specifications
| Feature | Specification |
|---|---|
| Designation | Holosun HS403R |
| Manufacturer | Holosun Technologies (China/USA) |
| Type | Micro reflex viewfinder (red dot) |
| 1x magnification | (non-magnifying) |
| Objective Lens Diameter | 20 mm |
| Red Dot Reticle | 2 MOA |
| Reticle color | Red |
| Impact adjustment | 1 MOA per click |
| Brightness settings | 12 levels (10 day + 2 night vision compatible) |
| Control | Rotary Switch with integrated battery |
| CR2032 battery (integrated into the rotary wheel) | |
| Battery life | 50,000 h (medium level) |
| Multi-layer anti-reflective | optical coating |
| Cast aluminum housing | , black anodized finish |
| Dimensions | 69.9 × 36.3 × 41.1 mm (L × W × H) |
| Weight | ~100 g (without mounting) |
| IP67 waterproof | (submersible up to 1 m) |
| Lower | 1/3 Co-witness (41.4 mm) + Low Mount (19.1 mm) mount included |
Operation and Technical Particularities
The HS403R is an open-reflex viewfinder: the light-up reticle is projected onto a partially reflective lens, allowing both eyes to be seen without tunneling. At 1x magnification, it does not change the perception of the target, which is ideal for fast engagement at close and medium distances.
The main feature of the HS403R is its side rotary switch that performs two functions: it serves both as a brightness selector — by turning the dial you go from one level to another until the OFF position — and as a battery compartment cover. To replace the CR2032, simply unscrew the dial slightly and slide the battery. This so-called “side battery access” design is appreciated because it does not require you to remove the sight from the weapon to change the battery, and it avoids any disturbance of the zero.
The 2 MOA (Minutes of Angle) reticle corresponds to about 5.8 cm at 100 meters — accurate enough for shooting from a distance, while remaining clearly visible in varying light conditions. The 12 brightness levels, 2 of which are compatible with night vision goggles, allow the red dot to be adapted to all lighting conditions, from full sun to total darkness. The multi-layer anti-reflective coating of the lenses improves light transmission and image clarity, a remarkable feature for this price segment.
Variants and Versions
The HS403 series is available in several variants. The HS403B is the most basic version, with the battery in the rear position and push buttons for adjustment. The HS403C incorporates a Solar Failsafe solar panel on the front, allowing solar energy to be operated in daylight and using the CR2032 only indoors or at night — this technology significantly extends the effective range. The HS403R (this model) opts for the rotary switch without Solar Failsafe. The HE403R is the “Elite” version with a more noble alloy housing and reinforced construction. Finally, the HE403R-GD offers a Gold Dot reticle for increased visibility in extreme lighting conditions, and the HE403C-GR offers a green dot with Solar Failsafe for users sensitive to color contrasts.
Users and Marketplace
The HS403R is primarily aimed at the civilian market, especially sport shooters, dynamic shooters (IPSC, 3-Gun), and users of AR-15 rifles or similar. Its light weight (100 g) makes it attractive for configurations aimed at minimizing overall weight. Some private security units and law enforcement agencies in countries with limited budgets have also adopted it as a service optics.
On the European market, the HS403R is distributed by several specialist dealers in Switzerland, France, Germany and Belgium. Its price positioning (80–150 CHF) makes it a serious entry-level viewfinder, well below the prices of an Aimpoint Micro T-2 (~1000 CHF) while offering appreciable optical quality and reliability for intensive recreational use.
Civil Possession in Switzerland
In Switzerland, the Holosun HS403R is an optical accessory that is not subject to any specific regulations. Its purchase is free for any adult, without a license required for the accessory itself. However, its use is conditional on the legal possession of the weapon on which it is mounted. For a semi-automatic rifle (AR-15, civilian SIG 550, etc.), the acquisition requires a weapons acquisition permit issued by the competent cantonal authority, in accordance with the Federal Weapons Act (Arms Act). The applicable conditions include: being at least 18 years old, not being under guardianship of general application, and not presenting a reason for refusal within the meaning of Art. 8 para. 2 Firearms Ordinance. The HS403R is available from several Swiss gunsmiths and online shops specializing in firearms accessories.
Conclusion
The Holosun HS403R is a simple and effective solution for the shooter looking for a compact, lightweight and reliable red dot sight without the premium features of higher models. Its rotary switch with built-in battery access provides a convenient ergonomic solution, and its 50,000 hours of battery life on the CR2032 make it a low-maintenance sight. It embodies the Holosun brand’s signature value for money, making high-performance red dot sights accessible to the masses.
