Holosun 407K, 507K Adapter for FN509

• FN 509-specific interface: This adapter plate is made to bridge the FN 509 optics-ready slide and the Holosun 407K/507K mounting standard, giving a clean and secure way to fit compact pistol optics without improvised solutions.
• Low-profile design: With KR 0.0 mm extension and 0 MOA inclination, the plate keeps the optic close to the slide for a more natural presentation and a less bulky carry setup.
• Aluminium construction: The aluminum body adds strength without unnecessary weight, helping preserve the handling balance of the pistol while still providing a stable mounting surface.
• Secure optic alignment: A precisely machined adapter helps the sight sit correctly on the slide, which supports repeatable installation and dependable zero retention under recoil.
• Built for carry and range use: The black protective finish and compact form make this mount well suited to everyday holster use, training, and general defensive pistol setups.

About the - Series

Holosun accessory mounts and adapter plates are built around the same practical design approach as the company’s pistol optics: expand compatibility, keep installation straightforward, and maintain a compact overall footprint. Within the brand’s lineup, these mounting solutions are intended for shooters who want to pair specific optics with specific handgun platforms without giving up a secure fit or sensible sight height.

For compact pistol red dots in particular, Holosun’s adapter plates focus on precise footprint matching, low-profile geometry, and durable metal construction that stands up to repeated recoil. Rather than changing the character of the handgun, they are designed to preserve handling and presentation while opening the door to proven optics such as the 407K and 507K. That makes this family especially relevant for concealed-carry pistols, defensive handguns, and range guns where compact dimensions matter as much as reliable mounting.

About the Holosun 407K, 507K Adapter for FN509

The Holosun 407K, 507K Adapter for FN509 is a dedicated handgun mount that allows a pistol with an FN 509 optics-ready interface to accept compact Holosun K-footprint sights. In practical terms, it gives shooters access to the smaller 407K and 507K optic format on a platform that would otherwise require a different mounting arrangement. That is especially useful when the goal is to keep a defensive or carry pistol trim, fast to present, and easy to manage in a holster.

The plate’s 0 MOA inclination and KR 0.0 mm extension show its purpose clearly: it is meant to act as a straightforward interface rather than alter the shooting geometry. Keeping the optic low on the slide helps preserve a natural sight picture and reduces the stacked height that can make a pistol feel top-heavy. The result is a setup that remains compact while still benefiting from a modern micro red dot.

Aluminium construction gives the mount the rigidity needed for slide-mounted use without adding unnecessary mass. Combined with the black protective finish, that makes it suitable for regular carry, training, and general hard use. Because the plate is built specifically for the Holosun 407K/507K mounting standard, it supports proper optic fit and alignment, which is critical for consistent installation and dependable zero retention over repeated firing cycles.

About Holosun

Holosun is a California-headquartered optics manufacturer focused on sights, lasers, and illumination systems for shooting, hunting, law enforcement, and military applications. The company says it has worked on optics and laser or infrared technologies since 2013, and its product history identifies the 403 Series as the starting point of its lineup in 2015.

Holosun expanded quickly into pistol and long-gun optics, introducing the 510C in 2016 and the 507C and 508T pistol sight series in 2017. The brand is also known for proprietary features such as Shake Awake, Solar Failsafe, and the Multi-Reticle System. Alongside its optics development, Holosun uses a global manufacturing network, which has helped it build a broad catalog of sights and mounting solutions for modern sporting, defensive, and professional use.

Main Features

• Manufacturer: Holosun
• Made in: China
• Mounting standard: Holosun 407K/507K
• Compatibility above: Holosun 407K/507K Mounting Standard
• Extension (KR): KR 0.0 mm
• Inclination: 0 MOA
• Material: Aluminium
• Color: Black

Warranty

Holosun provides a 2-year warranty for this adapter plate. This stated warranty period covers the product as a specific term in years.