1. Introduction
This manual provides instructions for the proper setup, operation, and maintenance of your HOLOSUN HE403B-GR / HS403B 2 MOA Green Dot Micro Sight. Please read this manual thoroughly before using the device to ensure safe and effective operation.
Image 1.1: Front view of the HOLOSUN HE403B-GR Micro Sight.
2. Package Contents
Verify that all items are present in the package:
- HOLOSUN HE403B-GR / HS403B Micro Sight
- Lower 1/3 Co-witness Mount (1.63")
- Low Mount (0.75")
- CR2032 Battery
- T10 L Key
- Lens Cloth
- Rubber Lens Cover
3. Setup
3.1. Battery Installation
- Unscrew the battery tray cover located on the side of the sight using the provided T10 L key.
- Insert the CR2032 battery with the positive (+) side facing upwards.
- Securely replace the battery tray cover.
3.2. Mounting the Sight
The sight includes two mounts: a lower 1/3 co-witness mount (1.63") and a low mount (0.75"). Choose the appropriate mount for your rifle or carbine application.
- Attach the desired mount to the bottom of the sight using the provided screws.
- Place the sight assembly onto your firearm's Picatinny or Weaver rail.
- Tighten the mount's cross bolt or quick-release lever to secure the sight firmly to the rail. Ensure it is stable and does not wobble.
Image 3.1: Angled view of the HOLOSUN HE403B-GR Micro Sight, demonstrating its compact size.
4. Operating Instructions
4.1. Power On/Off and Brightness Adjustment
- Power On: Press either the '+' or '-' button to turn on the sight.
- Brightness Adjustment: Use the '+' button to increase brightness and the '-' button to decrease brightness. There are 12 brightness settings: 10 for daylight and 2 for night vision compatibility.
- Power Off: Press and hold the '+' button for 3 seconds to turn off the sight.
4.2. Shake Awake Technology
The sight features Shake Awake technology to conserve battery life. When the optic detects no motion for a set period (default is 10 minutes), the LED will automatically deactivate. The slightest movement of the optic will instantly reactivate the LED to its last used brightness setting.
Image 4.1: Explanation of Shake Awake Technology.
4.3. Windage and Elevation Adjustment
The windage and elevation adjustments are located on the top and right side of the sight, respectively. Each click adjusts the point of impact by 0.5 MOA.
- Remove the protective caps from the adjustment turrets.
- Use a flathead screwdriver or the cap itself to turn the adjustment turrets.
- Turn the Elevation turret (top) clockwise to move the point of impact down, and counter-clockwise to move it up.
- Turn the Windage turret (right side) clockwise to move the point of impact right, and counter-clockwise to move it left.
- After zeroing, replace the protective caps.
Image 4.2: Side view of the sight, showing the windage adjustment turret.
4.4. Reticle Information
The HE403B-GR features a 2 MOA Green Dot reticle. The HS403B features a 2 MOA Red Dot reticle. Both models offer a clear, precise aiming point.
Image 4.3: Visual representation of the 2 MOA Green Dot and Red Dot reticles.
5. Maintenance
5.1. Cleaning
To maintain optical clarity, regularly clean the lenses with the provided lens cloth. For stubborn smudges, a small amount of lens cleaning solution designed for optics can be used. Avoid using harsh chemicals or abrasive materials.
5.2. Battery Replacement
Replace the CR2032 battery when the reticle dims significantly or fails to illuminate. Refer to Section 3.1 for battery installation steps.
5.3. Storage
When not in use, store the sight with the rubber lens cover installed to protect the lenses from dust and scratches. Store in a cool, dry place.
6. Troubleshooting
If you encounter issues with your HOLOSUN Micro Sight, refer to the following common problems and solutions:
- Reticle Not Visible:
- Check if the sight is powered on.
- Ensure the battery is correctly installed and has sufficient charge. Replace if necessary.
- Adjust brightness settings using the '+' button.
- Reticle Appears Dim or Flickers:
- Replace the CR2032 battery.
- Ensure battery contacts are clean and free of corrosion.
- Zero Not Holding:
- Verify that the sight is securely mounted to the firearm rail. Check all screws and mounting hardware.
- Ensure the adjustment turrets are not loose or accidentally moved.
If problems persist after attempting these solutions, please contact HOLOSUN customer support.
7. Specifications
| Model | HE403B-GR (Green Dot) / HS403B (Red Dot) |
| Reticle | 2 MOA Dot |
| Light Wavelength | 540nm (Green) |
| Magnification | 1x |
| Eye Relief | Unlimited |
| Parallax | Parallax Free |
| Power Source | CR2032 Battery |
| Battery Life | Up to 50,000 hours |
| Brightness Settings | 10 Daylight & 2 Night Vision |
| Window Size | 20mm Diameter |
| Housing Material | 6061 T6 Aluminum |
| Adjustment per Click | 0.5 MOA |
| W&E Travel Range | ±50 MOA |
| Item Weight | 4.32 ounces |
| Item Dimensions (LxWxH) | 2.44 x 1.18 x 1.45 inches |
| Compatible Devices | Air Rifle, Cross Bow, Pistol, Shotgun |
| Mounting Type | Standard mount (includes lower 1/3 co-witness and low mounts) |
8. Warranty & Support
8.1. Warranty Information
The HOLOSUN HE403B-GR / HS403B Micro Sight is covered by a Lifetime Warranty. For specific details regarding warranty coverage and terms, please refer to the official HOLOSUN website or contact customer support.
8.2. Customer Support
For technical assistance, warranty claims, or any other inquiries, please visit the official HOLOSUN website or contact their customer service department. Contact information can typically be found on the manufacturer's website.
