Content provided by Holosun
Holosun has introduced an updated version of its 507C pistol-mounted optic for 2026. Designated the 507C-X3, the new model retains the core features of the existing platform while adding a revised housing, changes to the lens presentation and an updated forward-facing light sensor.
The 507C-X3 is designed for use on handguns equipped with an RMR-footprint mounting plate. That footprint is widely used across optics-ready pistols and aftermarket slide systems, allowing the sight to work with a range of existing mounting hardware. Depending on the pistol and slide configuration, an adapter plate may still be required.
One of the main changes is the optic’s forward-facing photodiode, which monitors ambient light and adjusts reticle brightness. Positioning the sensor toward the front is intended to help the optic respond to the lighting conditions around the target rather than only the conditions surrounding the shooter.
This can be relevant when moving between areas with different levels of illumination, such as stepping from an indoor space into sunlight or aiming from a shaded position toward a brighter background. The optic also includes manual brightness controls for users who prefer to select their own settings.
The 507C-X3 offers 12 brightness levels, including 10 intended for daylight use and two compatible with night-vision equipment. Lockout and memory modes are included to help prevent unintentional setting changes and retain the previously selected brightness level.
Holosun’s Multi Reticle System remains part of the updated model. Users can select a 2 minute-of-angle dot, a 32 MOA circle or a combined circle-and-dot display. The smaller dot provides a defined aiming point, while the larger circle can be easier to locate within the window during presentation. Reticle selection may vary according to user preference, shooting distance and application.
The viewing window measures 0.91 by 0.67 inches, matching the general proportions of the previous 507C design. The sight has 1x magnification, unlimited eye relief and a multi-coated lens. Windage and elevation adjustments move the point of impact by 1 MOA per click, with an adjustment range of plus or minus 50 MOA.
The housing is machined from 7075-T6 aluminum and finished with a black hard-anodized coating. The optic measures 1.78 inches long, 1.31 inches wide and 1.1 inches high. It weighs 1.55 ounces.
Holosun lists the 507C-X3 with an IP67 ingress-protection rating. Under the rating standard, the first digit indicates protection against dust, while the second covers temporary water immersion under specified test conditions. The optic is also listed with a vibration rating of 5,000G.
Power is supplied by a side-loading CR1632 battery. The side tray allows the battery to be replaced without removing the sight from the slide, reducing the likelihood that the optic will need to be re-zeroed after routine battery changes.
The battery life can reach up to 50,000 hours, although actual runtime will depend on the selected reticle, brightness level, operating conditions and frequency of use. The sight also includes the company’s Shake Awake function, which places the optic into a low-power state after a period of inactivity and reactivates it when movement is detected.
Solar Failsafe is included as a secondary power feature. The solar system can help operate the reticle when sufficient light is available and provides an additional source of power if the battery is depleted. Its performance will depend on available ambient light.
The 507C-X3 will be offered with red, green and gold reticle options. The listed model numbers are 507CX3-RD-MRS, 507CX3-GR-MRS and 507CX3-GD-MRS.