Description
This Picatinny adapter raises your Holosun 509T optic to the preferred lower third cowitness height for improved sight picture and natural shooting position.
Mount your Holosun 509T-series red dot sight to any Picatinny rail system with this precision-engineered adapter that positions your optic at 1.63 inches above the rail. The lower third cowitness configuration allows your backup iron sights to remain visible in the bottom third of your optic window without cluttering your primary aiming point, giving you the best of both worlds: unobstructed red dot visibility with immediate iron sight backup capability. Constructed from CNC-machined aircraft-grade aluminum with military-spec hardcoat anodizing, this mount delivers a secure, wobble-free platform that maintains zero under recoil.
Key Features
- Lower 1/3 Cowitness Height: Positions optic at 1.63 inches for optimal head position and unobstructed red dot view while maintaining iron sight backup in the lower portion of the sight window
- Military-Grade Construction: CNC-machined from 6061 aircraft aluminum with Type III hard anodized finish for exceptional durability and corrosion resistance
- Secure Mounting System: Includes stainless steel torx head M3 screws that provide a tight, vibration-resistant connection between optic and mount
- Universal Picatinny Compatibility: Fits standard MIL-STD-1913 Picatinny rail systems on rifles, shotguns, and carbine platforms
Important Compatibility Notes
- Designed exclusively for: Holosun 509T-series enclosed red dot sights only
Why We Carry It
The 1.63-inch lower third cowitness height has become the preferred mounting standard for modern defensive and duty rifles, offering a more natural, heads-up shooting position compared to absolute cowitness mounts. This height reduces neck strain during extended use while providing a clearer sight picture acquisition. The Holosun 509T’s enclosed design already makes it one of the most durable pistol red dots on the market, and this mount extends that ruggedness to rifle applications. We stock this adapter because it’s the factory solution for customers mounting their 509T optics to AR-15 platforms, tactical shotguns, and pistol-caliber carbines, where the unique enclosed emitter design excels.
Frequently Asked Questions
What is the difference between lower 1/3 cowitness and absolute cowitness?
Lower 1/3 cowitness positions the optic slightly higher (1.63 inches versus approximately 1.42 inches), so your iron sights appear in the lower third of your optic window rather than directly centered with the red dot. This provides a clearer view through your optic while keeping backup sights visible. Absolute cowitness aligns the iron sights and red dot at the same height, which can clutter the sight picture but offers faster transitions between sighting systems.
Will this mount work with my Holosun 407C or 507C optic?
No, this mount is specifically designed for the Holosun 509T series only. The 509T uses a unique rail-clamp mounting system that differs from the 407C/507C footprint. Each Holosun model requires its specific compatible mount. The 407C and 507C models use a different mounting pattern and require mounts specifically designed for that footprint.
Can I use this mount on an AK platform or other non-AR rifles?
Yes, this mount will work on any firearm equipped with a standard Picatinny (MIL-STD-1913) rail system. While most commonly used on AR-15 pattern rifles, it functions equally well on AK rifles with Picatinny top covers, shotguns with optic rails, and pistol-caliber carbines. Just ensure your firearm has a Picatinny rail rather than a Weaver or proprietary rail system.
Spec Sheet
- Model: 509MNT-1.63-PIC
- Manufacturer: Holosun Technologies
- MPN: 509MNT-1.63-PIC
- UPC: 810047071082
- Mount Height: 1.63 inches (lower 1/3 cowitness)
- Material: CNC-machined 6061 aircraft aluminum
- Finish: Type III Hard Anodized, Black
- Rail Compatibility: Picatinny (MIL-STD-1913)
- Optic Compatibility: Holosun 509T series only
- Color: Matte Black
- Weight: Approximately 1.6 ounces
