Apex Optic Mount for Holosun 509T to FN MRD Pistols

Description

This Apex Optic Mount provides a direct, secure fit for the Holosun 509T on FN 509 pistols equipped with the FN Low Profile Optics Mounting System™. Machined from a single billet of steel with a black oxide finish, this mount is built to withstand the recoil of high-round-count training and competition.

The key advantage here is the elimination of stacking plates. An integrated locking key mounts directly into your FN 509 slide, removing the need for a separate MRD Insert. This means a lower, more stable mounting surface with fewer potential failure points. Your optic sits closer to the bore axis, which matters for maintaining zero and consistent sight alignment under rapid fire.

Key Features & Benefits:

• Direct Slide Integration: The integrated locking key engages directly with the FN Low Profile Optics Mounting System™. No adapter plates or extra inserts are required.
• Secure Holosun 509T Mounting: Designed specifically for the Holosun 509T footprint, this mount provides a rigid, repeatable platform. You get a solid lock-up that keeps the optic in place through extended range sessions and duty use.
• Steel Construction: CNC machined from billet steel, not aluminum. This adds durability and resistance to deformation under clamping force and impact. The black oxide finish provides corrosion resistance without adding thickness or glare.
• No MRD Insert Needed: This mount replaces the factory MRD insert and plate system entirely. This simplifies installation and reduces the overall height of the optic setup.

Fitment & Specs:

• Compatible Pistols: FN 509 series pistols with the FN Low Profile Optics Mounting System™. This includes models like the FN 509 Compact, FN 509 Tactical, and FN 545.
• Compatible Optic: Holosun 509T (all generations).
• Material: Billet steel.
• Finish: Black oxide.
• Installation: Direct mount to the slide. Use the provided screws and torque specifications for your optic and the mount-to-slide interface. No additional shimming or plate modification is needed.

For shooters who demand a rigid, low-profile mounting solution that doesn’t rely on stacked adapter plates, this mount delivers a direct path from the optic to the slide. It’s a practical upgrade for competition rigs and duty guns where reliability and a consistent zero are non-negotiable.