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

If you’ve got a Glock MOS pistol and a Holosun 509T optic, you’ve probably run into the same problem we hear about all the time at the shop: the 509T just won’t bolt directly to the factory MOS cut. The screw holes don’t line up, and the footprint is different. That’s exactly why this mount exists. It bridges the gap between your Holosun 509T and your Glock MOS slide, giving you a solid, repeatable mounting surface so you can actually use that closed-emitter dot without having to send your slide out for milling. Made here in the Free State of Arizona from billet steel with a black oxide finish, this mount is built to last and keeps your optic locked in tight, shot after shot.

Compatibility

• Glock MOS models: G17, G19, G22, G23, G31, G32, G34, G35, G40, G41 (Gen 4 and Gen 5 MOS)
• Holosun 509T (all generations, including X2 and RD models)
• Direct fit to factory Glock MOS slide – no adapter plates or slide modifications needed
• Mounting screws included in the package

Key Features

• Machined from billet steel for strength and rigidity – won’t flex or warp under recoil
• Black oxide finish resists corrosion and reduces glare
• Low-profile design keeps the optic close to the bore axis
• Includes all necessary mounting hardware
• Recommended torque: 15 in-lb on the screws
• Backed by Competition Trigger Works’ warranty

Install Difficulty

Difficulty: 2 out of 5 – Easy if you’ve got a torque driver. You’ll need a small flathead screwdriver or T10 Torx bit (depending on the screws), a torque wrench or driver that reads inch-pounds, and a clean rag for the slide surface. Most folks can knock this out in 10 minutes. We recommend cleaning the slide recess before installation and torquing the screws to 15 in-lb – no more, no less. Watch our install video on the product page if you want to see it done step by step.

Frequently Asked Questions

Will this mount work on a non-MOS Glock slide?

No. This mount is designed specifically for slides with the factory Glock MOS cut. If you have a standard Glock slide without the MOS footprint, you’ll need to have it milled for the 509T or use a different adapter system.

Does this mount require any permanent modification to my slide?

Not at all. It mounts directly to the existing MOS screw holes using the included hardware. No drilling, tapping, or slide modifications are needed. You can remove it and go back to your factory MOS cover plate anytime.

Will the optic co-witness with my factory iron sights?

That depends on your slide and sight height. On most MOS models, you’ll get a lower 1/3 co-witness with standard-height suppressor sights. If you’re running factory Glock sights, you may see the very bottom of the window. We recommend suppressor-height sights for a clean co-witness setup.

We ship this mount fast from our shop floor. If you have any questions about fitment for your specific Glock model, give us a call or drop us an email – we’re happy to help. Every mount is covered by our warranty against defects in materials and workmanship.