{"id":4633,"date":"2026-03-24T10:59:29","date_gmt":"2026-03-24T10:59:29","guid":{"rendered":"https:\/\/nextgun.ch\/wiki\/holosun-hs403b-the-compact-red-dot-rear-battery-viewfinder\/"},"modified":"2026-04-27T11:59:40","modified_gmt":"2026-04-27T11:59:40","slug":"holosun-hs403b-the-compact-red-dot-rear-battery-viewfinder","status":"publish","type":"wiki","link":"https:\/\/nextgun.ch\/en\/wiki\/holosun-hs403b-the-compact-red-dot-rear-battery-viewfinder\/","title":{"rendered":"Holosun HS403B | The Compact Red Dot Rear Battery Viewfinder"},"content":{"rendered":"\t\t
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The Holosun HS403B<\/strong> is a compact reflex-style red dot sight, manufactured by Holosun Technologies, designed for semi-automatic rifles and rifles. This model is distinguished by its battery compartment positioned on the rear panel and its push buttons for adjusting the brightness, offering a simple and intuitive grip in a lightweight 100 gram aluminum body. <\/p>\n\n

History and Development of the Holosun HS403B<\/h2>\n

Holosun Technologies is an American-Chinese company founded in 2013, with its American headquarters based in City of Industry, California. The brand has quickly established itself in the global market of tactical optics by offering sights that combine reliability, lightness and competitive prices compared to established references such as Aimpoint and EOTech. <\/p>\n

The HS403B belongs to the 403 series, Holosun’s entry range for single red dot rifle sights. This series offers several variations: the HS403B, the subject of this article, which adopts the most basic configuration with a battery in the rear position and push buttons; the HS403C, which integrates a Solar Failsafe solar panel on the front; and the HS403R, which replaces the buttons with a rotary switch integrating the battery compartment into the dial. The HS403B has been designed to meet the needs of users looking for a reliable, easy-to-use red dot sight with no superfluous features and an affordable price. Its sleek design with CR2032 battery in the rear position is familiar to users who have already handled Aimpoint type sights. <\/p>\n

The 403 series was a notable commercial success in Europe, North America and Asia, mainly as the main optic on civilian AR-15, AK and M4 rifles. The HS403B occupies the lower end of the Holosun range, with a retail price generally between 70 and 130 CHF depending on the retailer. <\/p>\n\n

Technical Specifications<\/h2>\n\n\n
Feature<\/th>Specification<\/th><\/tr><\/thead>\n
Designation<\/td>Holosun HS403B<\/td><\/tr>\n
Manufacturer<\/td>Holosun Technologies (China\/USA)<\/td><\/tr>\n
Type<\/td>Micro reflex viewfinder (red dot)<\/td><\/tr>\n
1x magnification<\/td>(non-magnifying)<\/td><\/tr>\n
Objective Lens Diameter<\/td>20 mm<\/td><\/tr>\n
Red Dot Reticle<\/td>2 MOA<\/td><\/tr>\n
Reticle color<\/td>Red<\/td><\/tr>\n
Impact adjustment<\/td>1 MOA per click<\/td><\/tr>\n
Brightness settings<\/td>12 levels (10 day + 2 night vision compatible)<\/td><\/tr>\n
Control<\/td>Two side push buttons (+ and \u2013)<\/td><\/tr>\n
<\/td>CR2032 battery (rear compartment)<\/td><\/tr>\n
Battery life<\/td>50,000 h (medium level)<\/td><\/tr>\n
Multi-layer anti-reflective<\/td> optical coating<\/td><\/tr>\n
Cast aluminum housing<\/td>, black anodized finish<\/td><\/tr>\n
Dimensions<\/td>69.9 \u00d7 36.3 \u00d7 41.1 mm (L \u00d7 W \u00d7 H)<\/td><\/tr>\n
Weight<\/td>~100 g (without mounting)<\/td><\/tr>\n
IP67 waterproof<\/td>(submersible up to 1 m)<\/td><\/tr>\n
Lower<\/td>1\/3 Co-witness (41.4 mm) + Low Mount (19.1 mm) mount included<\/td><\/tr>\n<\/tbody>\n<\/table>\n\n

Operation and Technical Particularities<\/h2>\n

The HS403B is an open-reflex sight: the light-up reticle is projected onto a partially reflective lens angled in front of the shooter’s eye, allowing both eyes to be aimed without tunneling or loss of field of view. At 1x magnification, it does not alter target perception, which is ideal for fast engagements at close and medium ranges. <\/p>\n

The main feature of the HS403B is its battery compartment positioned on the back side of the case, accessible via a screwed hatch. This traditional placement allows for quick replacement of the CR2032 without changing the mounting on the weapon or disturbing the zero. The two side push buttons (a + button and a \u2013 button) allow you to navigate between the 12 levels of brightness, 2 of which are compatible with night vision goggles. Pressing and holding a button turns off the sight. <\/p>\n

The 2 MOA reticle corresponds to approximately 5.8 cm at 100 meters. The multi-layer anti-reflective coating of the lenses improves light transmission and reduces flare. The IP67 resistance guarantees complete dust resistance and immersion up to 1 meter, making the viewfinder usable in all weather conditions. <\/p>\n\n

Variants and Versions<\/h2>\n

The HS403 series includes three main variants. The HS403B<\/strong> (this model) is the basic version with rear battery and push buttons \u2014 ideal for users looking for simplicity. The HS403C<\/strong> adds a Solar Failsafe solar panel on the front panel that allows the viewfinder to run on solar power outdoors, using the CR2032 only indoors or at night, greatly extending the practical battery life. The HS403R<\/strong> replaces the buttons with a rotary switch that integrates the battery compartment directly into the adjustment dial. The HE403 range offers “Elite” versions with more robust alloy housings, and the GD (Gold Dot) or GR (Green Dot) variants offer alternative color reticles for better visibility depending on the environment and lighting conditions. <\/p>\n\n

Users and Marketplace<\/h2>\n

The HS403B is mainly intended for the civilian sports market. Shooters practicing dynamic shooting (IPSC, 3-Gun), target shooting or simple plinker training will find an affordable, reliable sight without unnecessary complexity. Its light weight (100 g) makes it attractive for configurations that minimize weight, especially on civilian AR-15, AK-pattern and M4 rifles. <\/p>\n

On the European market, the HS403B is distributed by many specialist dealers in Switzerland, France, Germany, Austria and Belgium. Its price positioning (70\u2013130 CHF) makes it a serious entry-level sight, widely accessible compared to high-end references such as the Aimpoint Micro T-2 (~1,000 CHF). It is an excellent choice for a first red dot sight or an inexpensive replacement sight on a secondary weapon. <\/p>\n\n

Civil Possession in Switzerland<\/h2>\n

In Switzerland, the Holosun HS403B 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. 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 conditions include: being at least 18 years old, not under general guardianship, and not presenting a reason for refusal within the meaning of Art. 8 para. 2 LArm. The HS403B is available from many Swiss gunsmiths and online shops specializing in firearm accessories. <\/p>\n\n

Conclusion<\/h2>\n

The Holosun HS403B is the most accessible and simplest version of the 403 series, ideal for the shooter who wants to equip their rifle with a reliable red dot sight without unnecessary features. With 50,000 hours of battery life on the CR2032, IP67 waterproofing, a robust aluminum body and an attractive entry price, it perfectly embodies the Holosun philosophy: serious performance at a democratic price. <\/p>\n\n<\/div>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t","protected":false},"featured_media":4309,"template":"elementor_theme","meta":{"_acf_changed":false},"class_list":["post-4633","wiki","type-wiki","status-publish","has-post-thumbnail","hentry"],"acf":[],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/nextgun.ch\/en\/wp-json\/wp\/v2\/wiki\/4633","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/nextgun.ch\/en\/wp-json\/wp\/v2\/wiki"}],"about":[{"href":"https:\/\/nextgun.ch\/en\/wp-json\/wp\/v2\/types\/wiki"}],"version-history":[{"count":1,"href":"https:\/\/nextgun.ch\/en\/wp-json\/wp\/v2\/wiki\/4633\/revisions"}],"predecessor-version":[{"id":4634,"href":"https:\/\/nextgun.ch\/en\/wp-json\/wp\/v2\/wiki\/4633\/revisions\/4634"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/nextgun.ch\/en\/wp-json\/wp\/v2\/media\/4309"}],"wp:attachment":[{"href":"https:\/\/nextgun.ch\/en\/wp-json\/wp\/v2\/media?parent=4633"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}