Holosun 509 Mounting Plate for FNX-45 Tactical
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The Holosun 509PLT-FNX45 is a steel adapter plate that carries a 509 footprint enclosed sight on the factory optic cut of an FNX-45 Tactical slide.
The 509 series uses a rear-lug footprint of Holosun's own, which does not match a factory RMR or RMSc cut. This plate is the piece that bridges the gap, and it is the only reason the two ever meet.
Holosun make it in steel with a corrosion-resistant finish, and both sets of fasteners come with it: the screws that hold the plate down to the slide, and the screws that hold the sight down to the plate. That matters more than it sounds, because a plate arriving without the second set is the most common way one of these ends up in a drawer. Holosun do not publish a weight for the plate.
On the pistol side it is cut for FNX-45 Tactical slides that left the factory optics-ready. On the optic side it takes the 509 footprint — the HS509T X2, the HE509T X2 and the HE509T-X2-GD. Be clear about what it does not do: an RMR-pattern sight such as a 507C or 407C will not sit on it, and neither will an RMSc-pattern 507K or 407K. Those are different bolt spacings and different lug arrangements, not a matter of forcing the screws.
One slide, one footprint: FNX-45 Tactical to Holosun 509. For other hosts, Holosun make the same plate for the FN 509 Tactical, the Glock MOS 9mm and the CZ P10, plus a version for 507C and RMR-cut slides. If the 509T is going on a rail rather than a slide, the 509T Picatinny mount is the part you want.
| Type | Optic adapter plate |
|---|---|
| Optic footprint | Holosun 509 (509T) |
| Fits | FNX-45 Tactical optics-ready slides |
| Material | Steel, corrosion-resistant finish |
| Hardware | Plate-to-slide and optic-to-plate screws included |
| Brand | Holosun |
| MPN | 509PLT-FNX45 |
A small part, but the one that decides whether the sight goes on at all. Order the 509PLT-FNX45 today — imported from the USA with all duties paid by us and dispatched tracked from the UK in 7–10 business days, with nothing to pay on delivery.
Explore more: Optic Mounts, 509 Plate for RMR-Cut Slides or browse all Holosun.
| Brand | Holosun |
|---|---|
| Part no. | 509PLT-FNX45 |
| Category | Optic Mount |
| Barcode | 810047071044 |
£5 tracked UK delivery on every order via Royal Mail Tracked 24. Our products are ordered in from the manufacturer rather than held in UK stock, so please allow 7 to 10 business days (Monday to Friday, excluding bank holidays) from the date of your order for it to reach you. Tracking details are emailed on dispatch. UK delivery only.
You have 30 days from receiving your order to cancel it for any reason, then 14 days to send it back unused and in its original packaging. Faulty, damaged or incorrect items are replaced or refunded and we cover reasonable return postage. Refunds go back to your original payment method within 14 days of receiving the return.
7 to 10 business days from the date of your order. Every order is sent Royal Mail Tracked for a flat £5 and you receive tracking details by email when it is dispatched.
Yes. We list only genuine parts and optics from the brands shown, ordered in from the manufacturer for your order.
Compatibility notes on this page come from the manufacturer. If you are unsure, email us with your make and model before ordering and we will check rather than guess.
Yes. Bundle & Save applies automatically in your basket: 5% off when you buy 2 items, 10% off at 3 items and 15% off at 4 or more. It works across the whole range, so you can mix and match, and there is no code to enter.
Yes — you have 30 days from delivery to cancel for any reason, as long as the item is unused and in its original packaging. See our returns policy for the details.
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