Apex Optic Mount for Holosun 509T to FN MRD Pistols
$69.00
Mount your Holosun 509T directly to your FN 509 or FN 545 slide with no adapter plates or MRD inserts. Machined from billet steel with an integrated locking key, the Apex Optic Mount delivers a rock-solid, repeatable zero.
Available for delivery across the United States.
Description
If you’re running an FN 509 with the factory Low Profile Optics Mounting System and want to mount a Holosun 509T without stacking plates or fussing with adapter inserts, the Apex Optic Mount for Holosun 509T to FN MRD Pistols is the solution you’ve been looking for. This mount is machined from a single billet of steel, black oxide finished, and designed to lock directly into the FN slide—no MRD insert needed. It eliminates the extra layers that can introduce play or shift your zero, giving you a solid, repeatable mounting platform for your 509T.
| Manufacturer | Apex Tactical Specialties |
|---|---|
| Model | Apex Optic Mount for Holosun 509T to FN MRD Pistols |
| Material | Billet steel (per manufacturer specs) |
| Compatibility | FN 509 series with FN Low Profile Optics Mounting System™ (FN 509, FN 509 Compact, FN 509 Midsize, FN 509 Tactical, FN 545) |
| Finish | Black oxide |
| Weight | 0.6 oz (per manufacturer specs) |
| Condition | New |
Key Features
- Integrated Locking Key – This mount uses a machined locking key that mates directly to the FN slide’s factory cut. Why it matters: You don’t need to buy a separate MRD insert or adapter plate. No stacking means fewer failure points and a more repeatable zero.
- Billet Steel Construction – Machined from a solid block of steel, not cast or MIM. Why it matters: Steel resists flex under recoil and holds zero better than aluminum or polymer mounts. It’s built for the long haul.
- Black Oxide Finish – A traditional, low-glare finish that resists rust and wear. Why it matters: Black oxide doesn’t add thickness or reflect light, and it’s easy to touch up if you ever ding the mount.
- Designed for Holosun 509T – The mounting footprint is cut specifically for the 509T’s unique shape and screw pattern. Why it matters: No shims, no filing, no guesswork. The optic sits flush and secure.
- Eliminates Plate Stacking – Mounts directly to the FN slide without an MRD insert. Why it matters: Fewer screws and layers reduce the chance of loosening under recoil, and your optic sits lower for a better co-witness with factory iron sights.
Who It’s For
This mount is for the shooter who owns an FN 509 or FN 545 with the FN Low Profile Optics Mounting System and wants to run a Holosun 509T. It’s for the guy who doesn’t want to mess with adapter plates, who values a direct, steel-to-steel connection. If you’ve ever had a red dot shift zero because of a plastic plate or a loose insert, this mount is your answer.
Pros and Cons
- Pro: Direct mount to FN slide – no MRD insert required.
- Pro: Billet steel – stronger and more rigid than aluminum or polymer mounts.
- Pro: Low-profile design – allows for lower optic height and better co-witness.
- Con: Only works with FN 509 series pistols that have the Low Profile Optics Mounting System. Not compatible with standard dovetail mounts or other pistol brands.
- Con: The black oxide finish can wear with heavy holster use, though it’s easy to touch up with cold blue.
Comparison: Apex vs. Other Optic Mounts
| Feature | Apex Optic Mount | Zev Technologies FN Mount | Lone Wolf Distributors FN Plate |
|---|---|---|---|
| Material | Billet steel | 7075 aluminum | 6061 aluminum |
| Finish | Black oxide | Black anodized | Black anodized |
| Requires MRD Insert? | No – integrated locking key | Yes – uses FN factory insert | Yes – uses FN factory insert |
| Weight | 0.6 oz | 0.4 oz | 0.5 oz |
| Price | $60 | $85 | $45 |
| Optic Compatibility | Holosun 509T only | Multiple footprints | Multiple footprints |
The Apex mount is the only one here made from steel, and the only one that eliminates the need for a separate MRD insert. That direct engagement with the slide is a real advantage for maintaining zero.
FAQ
Does Holosun make Sig optics?
No, Holosun does not manufacture optics for Sig Sauer. Holosun produces its own line of red dot sights and reflex sights under the Holosun brand. Sig Sauer uses its own ROMEO series optics, which are made in partnership with other manufacturers. However, many Holosun optics, including the 509T, can be mounted to Sig pistols using the correct adapter plate. For FN pistols, the Apex mount is designed specifically for the Holosun 509T.
Does Holosun make good optics?
Yes, Holosun makes good optics. They are widely used by law enforcement, competitive shooters, and everyday carriers. The Holosun 509T is a rugged, enclosed-emitter red dot with a titanium housing and multi-reticle system. It’s known for reliable battery life, clear glass, and a durable build. For the price, it competes directly with optics costing twice as much. Per industry surveys, Holosun holds roughly 30% of the aftermarket pistol red dot market, which speaks to their popularity and reliability.
Will this mount work on an FN 545?
Yes. The FN 545 uses the same FN Low Profile Optics Mounting System as the FN 509 series. The Apex Optic Mount is fully compatible with the FN 545 slide.
Do I need to buy any extra hardware?
No. The mount includes the integrated locking key and uses the factory screws from your FN pistol. You will need the screws that came with your Holosun 509T to attach the optic to the mount.
This mount is a clean, no-nonsense way to mount your Holosun 509T to an FN 509 or FN 545. It’s built from steel, it’s simple to install, and it holds zero.
✓ Nationwide delivery (all 50 states)
✓ Ships 1-2 business days
✓ 30-day returns
✓ Secure checkout
Browse more: FN Parts & Accessories | Optic Mounts & Plates | Holosun Optics
Last updated: April 2026
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