Apex Optic Mount for Holosun 509T Optic to Glock MOS Pistols

This steel optic mount adapts the Holosun 509T to any Glock MOS slide. It replaces the factory MOS cover plate and provides a stable, direct-mount interface for the 509T’s proprietary footprint. The key issue this solves: the 509T does not share the standard RMR or DPP footprint used by most MOS adapter plates, so without this specific mount, you cannot attach the 509T to a Glock MOS slide.

Compatibility

• Glock MOS slides (G17 Gen5 MOS, G19 Gen5 MOS, G45 MOS, G34 Gen5 MOS, G41 MOS, and all other factory MOS-cut slides)
• Holosun 509T (all generations: 509T X2, 509T RD, etc.)
• NOT compatible with non-MOS Glock slides or slides cut for RMR/DPP footprints

Key Features

• Material: machined billet steel, black oxide finish
• Direct mount to factory MOS slide – no additional adapter plates required
• Includes mounting screws (two screws for the mount to slide, two screws for the optic to mount)
• Recommended torque: 15 in-lb on all screws
• Manufactured in the Free State of Arizona

Install Difficulty

2 out of 5. Tools needed: T10 Torx driver (for mount-to-slide screws), 1.5mm hex key (for 509T screws), torque wrench capable of 15 in-lb (recommended). Clean the slide channel before installation. No fitting or modification required.

FAQ

Does this mount work with the Holosun 509T X2?

Yes. The 509T footprint is identical across all 509T generations. This mount fits the X2, original 509T, and 509T RD.

Will this mount co-witness with factory Glock MOS sights?

Not with standard-height MOS sights. The 509T sits higher than an RMR. You will need suppressor-height sights (approx. 0.400–0.450″ front / 0.485–0.500″ rear) for a lower 1/3 co-witness.

Can I use this mount on a Glock 43X/48 MOS?

No. The 43X/48 MOS uses a different footprint (Shield RMSc cut). This mount is for full-size and compact Glock MOS slides (17, 19, 34, 45, 41, etc.).

Shipping & warranty: Ships same business day if ordered before 2pm ET. Backed by the manufacturer’s limited lifetime warranty against defects in material and workmanship.