The American Defense AD-509T QD Red Dot Mount for Holosun 509T, Absolute Co-Witness is an American Defense Mfg. quick-detach mount for optics using the Holosun 509T footprint, at absolute co-witness height. It clamps to a Picatinny rail with ADM's patented Auto Lock quick-detach lever, which self-adjusts to in-spec and out-of-spec Picatinny rails without tools and returns to zero when refitted.
How It Compares
This mount is cut for the Holosun 509T footprint and nothing else — a 509T will not sit on an RMR-pattern mount and vice versa. The same mount is available as AD-509T at low and AD-509T at lower 1/3 co-witness. If you do not need quick-detach, Holosun's own fixed 509T Picatinny mounts (0.82in low profile and 1.63in lower 1/3) are the alternatives. For other footprints see the AD-RMR-LW mount for Trijicon RMR and SRO, or the AD-MRO-LW mount for Trijicon MRO. Browse all red dot & optic mounts. Shop the full American Defense Mfg. range. New to this? Read our guide: Co-Witnessing Iron Sights with a Red Dot.
Ideal For
- Practical and competition rifle stages shot at speed
- Practical shotgun, where a fast, unmagnified sight picture wins
- Quick-detach removal for travel, cleaning and locked transport
- Airsoft and training rifles that share a red dot with a live-fire host
Key Features
- Fits: Holosun 509T footprint
- Height: Absolute co-witness
- Mount: Picatinny, using ADM's patented Auto Lock quick-detach lever
- Weight: Around 2.3 oz
- Material: 6061-T6, Type III hardcoat
- Return to zero: Auto Lock lever returns the optic to zero when refitted
What's Included
- 1 × American Defense AD-509T Holosun 509T QD Mount Absolute Co-Witness
- Mounting hardware
Technical Specifications
Fits | Holosun 509T footprint |
Mount | Picatinny (Auto Lock QD) |
Height | Absolute co-witness |
Material | 6061-T6, Type III hardcoat |
Weight | ~2.3 oz |
US Shipping & Support
Shipped from D&R Sports Center in the USA with fast, tracked delivery. Questions on fit, mounting or which model suits your setup? Our team is glad to help before and after your purchase.
Frequently Asked Questions
Which optics fit this mount?
Optics using the Holosun 509T mounting footprint. It is not cut for the Trijicon RMR, Trijicon MRO or Leupold DeltaPoint Pro footprints.
What height does this mount give?
This version is absolute co-witness height, which sits the dot in line with AR-height iron sights, so irons and dot align through the same window.
Does this mount return to zero after removal?
Yes. It uses American Defense Mfg.'s patented Auto Lock quick-detach lever, which self-adjusts to the rail and returns the optic to zero when refitted, so it can be taken off for travel or cleaning and put straight back on.
What rail does this mount fit?
A MIL-STD-1913 Picatinny rail. The Auto Lock lever self-adjusts to in-spec and out-of-spec rails without tools.
How much does this mount weigh?
It weighs around 2.3 oz.
