Holosun 509T Mounts – EGW RMR Dovetail & Picatinny Solutions

Holosun 509T Compatibility Guide: EGW RMR Mounts and Adapter Requirements

The Holosun 509T uses its own clamp-style mounting interface. It does not attach directly to an RMR mount. An adapter-based setup requires an RMR-to-509T adapter and a compatible RMR base that fits your exact firearm or rail.

Holosun lists an RMR-to-509T adapter among the included accessories for the HE509T X2. When choosing an EGW base, check the firearm model, rear sight cut or optics-ready slide interface, and the product's fitment exclusions. Confirm the complete mount-and-adapter combination before ordering.

Holosun 509T optic and EGW mounting setup — Choose the firearm-specific EGW base, then verify the RMR-to-509T adapter and hardware for the complete assembly.

Check both mounting interfaces: the EGW base must fit the firearm, and the adapter must connect that base to the 509T. An RMR-compatible base is not a direct 509T mount. Dovetail mounts and optics-ready slide plates are different products.

EGW RMR Base Options by Firearm

The products below are RMR bases to evaluate for an adapter-based setup. Each still requires a compatible RMR-to-509T adapter; this table does not establish direct 509T fitment. Open the product page for its complete fitment list and current price.

RMR bases: firearm fitment and exclusions
Firearm or mounting interface	EGW base	Fitment to check
1911 with a compatible Novak-style rear sight cut	Novak RMR mount, SKU 49511	Verify the actual rear sight cut and the listed firearm. A 1911 model name alone does not identify its dovetail. Some applications require fitting.
Listed CZ 75, SP-01, Phantom, 85, 97, P-01 and PCR variants	CZ RMR dovetail mount, SKU 49526	Does not fit CZ P-07 or P-09. SP-01 Shadow fitment requires the checks on the product page. Do not treat this as an optics-ready plate for a Shadow 2 OR or P-10 C OR.
Listed non-optics-ready SIG P220, P226, P229, P320 and P210A Standard variants	SIG RMR dovetail mount, SKU 49518	Does not fit optics-ready SIGs, SIG 1911s, P220 10mm Hunter, P210 Target or P365. Check the full fitment list for your exact variant.
Listed Glock models with a compatible rear sight dovetail	Glock RMR dovetail mount, SKU 49513	Does not fit Glock MOS models or Glock slides already cut for optics. Use the product's listed model fitment.
1913 Picatinny rail	RMR / Holosun C Series Picatinny mount, SKU 49600	Fits the 1913 Picatinny interface; does not fit Weaver rails. Verify adapter clearance and the height of the complete assembly for your application.

Have an optics-ready pistol? Identify the slide's exact optic interface and select a plate designed for that model. A Shadow 2 OR, P-10 C OR, Glock MOS or optics-ready SIG should not be grouped with an ordinary rear-sight dovetail application.

Browse EGW RMR mounts and optic plates or contact EGW with your firearm model, slide type and optic model for help selecting the complete combination.

Parts to Confirm Before Ordering

Firearm-specific base: verify the EGW SKU, rear sight cut or rail interface, and all listed exclusions.
RMR-to-509T adapter: verify compatibility with your optic and the selected base. Check the accessories supplied with your particular optic.
Hardware: confirm the screw specification and length for the actual base-and-adapter combination. Hardware supplied for a direct RMR installation should not automatically be assumed correct for a stacked adapter.
Clearance and sight height: assess the complete assembly, including the base, adapter and optic. Adapter thickness and optic window height are different measurements.

Installation References

Use the instructions for the exact EGW mount, adapter and Holosun optic. The base, adapter and optic clamp are separate connections; follow the specified hardware and torque for each. EGW recommends installation and inspection by a qualified gunsmith.

For optic specifications and included accessories, see Holosun's HE509T X2 product information. Holosun also provides information about its 509PLT-507C RMR-to-509 adapter.

Holosun 509T Mounting FAQs

Does the Holosun 509T fit directly on an RMR mount?

No. The 509T has a clamp-style interface that differs from the RMR footprint. An RMR base requires a compatible RMR-to-509T adapter. A dedicated 509T mount is another option when available for your application.

Is an RMR-to-509T adapter included with the optic?

Holosun lists an RMR-to-509T adapter as an included accessory for the HE509T X2. Check the package contents for your exact purchase, especially a used optic or seller-specific bundle.

Will the listed Glock or SIG dovetail mount fit an optics-ready pistol?

The Glock SKU 49513 excludes MOS models and slides already cut for optics. The SIG SKU 49518 excludes optics-ready SIGs. Choose a mounting solution designed for your exact slide interface instead of assuming a dovetail mount will fit.

Will I retain iron sight co-witness?

An EGW rear-sight dovetail mount replaces the rear sight, so the original front-and-rear sight pair is not retained. With an optics-ready or Picatinny setup, co-witness depends on the actual mount, adapter, optic and iron sight heights.

How much height does the adapter add?

Use the specification for your exact adapter. Adapter thickness is not the same as the height from the firearm or mount surface to the optic window. The complete assembly height depends on the base, adapter and optic.

Shop EGW RMR Mounts and Optic Plates

Need fitment help? Call (215) 538-1012 or email info@egwguns.com.