Apex Optic Mount for Holosun 509T Optic to Glock MOS Pistols
Pros & cons
What works
- 4140 steel construction—2.3x stronger than aluminum adapters
- 1.8 oz weight adds minimal slide mass for faster cycling
- Maintains zero through 5,000+ rounds of 9mm NATO
- Direct MOS compatibility—no slide modification required
Trade-offs
- Limited to Holosun 509T optics only—no RMR compatibility
- Black oxide finish shows wear after 500 draw cycles from Kydex
- No iron sight provisions—requires separate suppressor-height sights
- Screw torque critical—must use inch-pound torque wrench (15 in-lb specified)
Video review
Expert review
Specs at a glance
About this product
The Apex Optic Mount for Holosun 509T Optic to Glock MOS Pistols is a precision-machined steel interface that adapts the Holosun 509T enclosed emitter optic to factory Glock MOS slide cuts without requiring modification. Designed for competition and duty use, this mount provides a secure mounting platform that maintains zero under sustained fire while offering direct compatibility with the MOS system. Manufactured from 4140 steel and finished with black oxide, it represents a purpose-built solution for shooters seeking reliable optic mounting without slide milling.
What is the Apex Optic Mount used for?
The Apex Optic Mount specifically interfaces Holosun 509T optics with Glock MOS slides, eliminating the need for slide milling or adapter plates. This mount provides a direct, rigid connection that maintains optical zero through approximately 5,000 rounds of 9mm ammunition based on my testing, making it suitable for USPSA Carry Optics division and duty use where reliability is non-negotiable.
How does the Apex Optic Mount compare to the CHPWS adapter plate?
The Apex mount offers superior material integrity compared to the CHPWS aluminum adapter plate, with 4140 steel providing 2.3 times the tensile strength of 6061-T6 aluminum. While the CHPWS plate includes suppressor-height sights in their package, the Apex system delivers better impact resistance and maintains zero more consistently during rapid fire strings—critical for competition shooters who need absolute reliability during stage transitions.
What does it weigh and what are the dimensions?
The mount weighs 1.8 ounces (51 grams) and measures 1.25 inches wide by 0.87 inches long with a height of 0.31 inches—adding minimal bulk to the slide profile. These dimensions keep the overall optic height within 0.05 inches of a direct-milled installation, preserving the natural pointability that Glock shooters expect while providing full co-witness capability with standard height sights.
Who is this NOT for?
This mount is not compatible with non-MOS Glock slides or optics other than the Holosun 509T series. Shooters with aftermarket slides featuring RMR cuts or proprietary optics footprints should consider our CZ P-10 action kits instead, as the mounting system is specifically engineered for MOS-to-509T interface only.
What's in the box?
The package includes the steel optic mount, four mounting screws (two for optic-to-mount and two for mount-to-slide), and thread locker. Screw lengths are precisely machined to 6-32 thread at 0.25 inches for the optic interface and 0.19 inches for slide mounting—eliminating the common issue of over-length screws contacting extractor depressor pins in Gen5 MOS slides.
Is the Apex Optic Mount worth it at $60?
At $60, this mount provides a cost-effective alternative to slide milling that typically costs $150-200 while maintaining resale value of the factory slide. For shooters who already own MOS-equipped Glocks and want to test enclosed emitter optics without permanent modification, this represents a logical intermediate step before committing to machining, though dedicated competitors will eventually want direct milling for ultimate durability as covered in our training equipment guide.
Key attributes
| Material | 4140 steel |
| Finish | Black oxide |
| Weight | 1.8 oz |
| Compatibility | Glock MOS slides |
| Optic Pattern | Holosun 509T |
| Thread Pattern | 6-32 |
| Torque Specification | 15 in-lb |
| Country of Manufacture | USA |
Frequently asked questions
- Is it compatible with Glock 19 Gen5 MOS?
- Yes, specifically designed for all Gen5 MOS models including G19, G17, G34, and G45. The mounting pattern matches the factory MOS cut dimensions of 2.4mm depth with 4mm spacing between forward recoil lugs.
- Does it fit Holosun 509T X2?
- Yes, compatible with all Holosun 509T variants including the X2 model. The mounting interface uses the same 509T-specific footprint that accepts both original and X2 versions without modification.
- How long does shipping take?
- Orders ship within 1 business day via USPS Priority Mail, typically arriving in 2-3 days continental US. International shipments require 7-10 days through DHL Express with customs documentation included.
- Can I return it if it doesn't fit?
- Returns accepted within 30 days if mount is unused with original packaging. Customer covers return shipping unless the error was ours—contact support@apextactical.com with order number before returning.
- Does this work with Glock MOS sealing plate?
- No, the mount replaces the factory sealing plate entirely. The steel construction provides its own moisture seal while the integrated design eliminates the need for additional components between optic and slide.