For Holoson – Apex Optic Mount Screw Set for FN MRD Pistols with an Apex mount for RMR Footprint Optics

What It Is

This is a dedicated screw set for mounting Holosun optics (RMR footprint) onto FN MRD pistols that use an Apex optic mounting plate. The set includes the correct thread pitch, length, and head profile to secure your optic without interference with the slide or extractor. Solves the common problem of aftermarket screws being too long (binding the extractor spring) or too short (insufficient thread engagement).

Compatibility

• FN 509 MRD (all generations)
• FN 509 Compact MRD
• FN 509 Tactical MRD
• FN 509 LS Edge
• FN Reflex MRD
• Requires Apex MRD mounting plate for RMR footprint optics
• Compatible with Holosun 407C, 407K, 507C, 507K, 508T, 509T, EPS, EPS Carry (when using RMR footprint plate)

Key Features

• Precision-ground 6-40 thread pitch
• Correct length for RMR footprint optics on Apex plate
• Stainless steel construction, black oxide finish
• Hex head (0.050″ Allen) – no stripping with standard torque values
• Sold as a set: 4 screws (2 optic-to-plate, 2 plate-to-slide)
• Includes thread locker compound (pre-applied or separate vial depending on batch)

Install Difficulty

2 out of 5
Tools needed: 0.050″ hex driver, torque wrench (recommended 12-15 in-lbs for optic screws), blue thread locker (if not pre-applied). Remove existing screws, clean threads, apply thread locker, torque to spec. No fitting or modification required.

FAQ

Can I use these screws with a factory FN optic plate?

No. These screws are specifically sized for the Apex MRD mounting plate. Factory FN plates use a different thread pitch and screw length. Using these in a factory plate may cause extractor binding or inadequate engagement.

Will these work with a Trijicon RMR?

Yes, the RMR footprint is shared between Trijicon and Holosun optics. These screws will secure a Trijicon RMR or SRO to the Apex plate, provided the optic uses standard RMR mounting holes (not the RMRcc or RMSc pattern).

Do I need to shorten the screws?

No. These are pre-cut to the correct length for the Apex plate and FN slide. If you experience extraction issues after installation, verify the plate is fully seated and that you have not over-torqued the screws (which can compress the plate).

Shipping & Warranty

Ships same business day if ordered before 2 PM ET. Standard USPS First Class included; upgrade to Priority at checkout. Manufacturer warranty covers defects in materials or workmanship – no-hassle replacement within 30 days of delivery.