Replacement screw set for securing an RMR-footprint optic to an Apex optic mount on FN MRD-series pistols. This kit includes the correct-length fasteners to replace lost, stripped, or incorrect screws when mounting a Trijicon RMR or other RMR-pattern optic to an Apex mount on your FN handgun. Eliminates guesswork with thread pitch and length mismatches that can damage the mount or optic housing.
Compatibility
- FN 509 MRD (all variants with Apex optic mount installed)
- FN 509 Compact MRD (with Apex optic mount)
- FN 509 Tactical MRD (with Apex optic mount)
- FN 502 MRD (with Apex optic mount)
- Fits any Apex FN MRD mount designed for RMR-footprint optics (Trijicon RMR, Holosun 407C/507C/508T, Swampfox Justice, etc.)
- Does not fit factory FN mounting plates or non-Apex aftermarket mounts
Key Features
- Two (2) mounting screws – correct length for Apex mount + RMR-pattern optic
- Precision-ground threads – 6-40 or M3 specification (verify per your mount generation)
- Black oxide finish – resists corrosion, reduces galling during installation
- Includes small tube of medium-strength threadlocker (blue)
- Direct replacement for OEM Apex hardware – no modification or shimming required
Install Difficulty: 1 / 5
Tools needed: T10 Torx driver or 3/32″ hex key (depending on screw head). Apply one drop of included threadlocker to each screw, torque to 12-15 in-lbs. No fitting, filing, or optic modification required. Estimated time: 5 minutes.
FAQ
Will these screws work with a Holosun 407K or 507K (K-series) on an Apex mount?
No. K-series optics use a different footprint (Shield RMSc) and require a separate adapter plate or Apex mount specifically cut for that pattern. This set is for RMR-footprint optics only.
I lost one screw from my original Apex mount kit – can I buy just one?
This set is sold as a pair. We recommend keeping the spare in your range bag. If you need a single screw for a non-RMR application, contact customer service with your mount model and optic type.
Are these screws longer than the ones that came with my Apex mount?
No. These are the same length as the original hardware supplied with your Apex mount. If you are using a different optic (e.g., a thicker RMR model), verify screw engagement depth – minimum 4 full threads into the optic is required. Do not use these screws with a factory FN mounting plate.
Shipping: Ships same business day if ordered before 2 PM ET. Warranty: 1-year replacement guarantee against manufacturing defects. Threadlocker included.
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