Apex Optic Mount for RMSc/507K – FN 509

This Apex Optic Mount is the direct, no-fuss solution for mounting a Shield Sights RMSc or Holosun 507K red dot onto your FN 509 pistol. At $65, it’s built for shooters who want a solid, reliable fit without paying for extras they don’t need. Machined from a single billet of steel and finished in black oxide, this mount is designed to handle hard use and keep your optic locked in place.

It’s made specifically for the FN Low Profile Optics Mounting System™ on your FN 509 slide. If your pistol has the MRD cut—like the FN 509 Tactical, MRD, or similar models—this mount gives you a direct, secure platform for the most popular micro red dots. No adapters, no shims, no guesswork.

Key Specs & Fitment:

• Material: Billet steel, black oxide finish
• Compatibility: FN 509 models with FN Low Profile Optics Mounting System™
• Optic support: Shield Sights RMSc and Holosun 507K (also fits 407K, EPS, and EPS Carry with the same footprint)
• Mounting hardware: For RMSc optics, use the “514” screws that came with your FN 509 Tactical or MRD. For the 507K, use the screws included with this mount
• Installation: Direct mount to your FN 509 MRD cut slide—no plate adapter needed

Real Benefits for Your Build:

• Steel construction, not aluminum: This mount holds up to repeated recoil and holster wear without stripping or cracking. Black oxide finish resists rust and glare.
• Specific fit, no slop: Engineered to match the FN Low Profile system exactly. Your optic sits low and tight against the slide, keeping your co-witness with iron sights intact.
• Two screw sets included: No need to hunt down extra hardware. Use the right screws for your optic right out of the box.
• Bulk-friendly pricing: At $65, this is a straight-ahead upgrade for anyone running multiple FN 509s or outfitting a fleet. Stock up and save.
• No gunsmith required: Simple swap with basic tools. Torque to spec and you’re zeroed.

Whether you’re adding a red dot for faster target acquisition or just want a more durable mounting solution than factory plastic