American Defense AD-509T Holosun 509T QD Mount Low – AD-509T-L-STD

The American Defense AD-509T Holosun 509T QD Mount Low is an American Defense Mfg. quick-detach mount for optics using the Holosun 509T footprint, part number AD-509T-L-STD, at low 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 stocked as AD-509T at absolute co-witness and AD-509T at lower 1/3 co-witness. Holosun's own Holosun 509T Picatinny Mount 0.82in low profile and Holosun 509T Picatinny Mount 1.63in lower 1/3 are the fixed alternatives if you do not need quick-detach. For other footprints see the AD-RMR-LW mount for Trijicon RMR and SRO, or the AD-MRO-LW mount for Trijicon MRO. Read our guide to co-witness heights and the red dot footprint compatibility chart, or browse every red dot sight mount we stock.

Ideal For

• Civilian Service Rifle and practical rifle stages shot at speed
• Straight-pull and practical shotgun where a fast, unmagnified sight picture wins
• Quick-detach removal for travel, cleaning and lockable transit
• Airsoft and training rifles that share a red dot with a live-fire host

Key Features

• Fits: Holosun 509T footprint
• Height: Low
• 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

Technical Specifications

What's Included

• 1 × American Defense AD-509T Holosun 509T QD Mount Low (AD-509T-L-STD)
• Mounting hardware

Warranty

Covered by the American Defense Mfg. lifetime warranty against defects in materials and workmanship.

UK Delivery & Support

Every order is dispatched tracked from our UK warehouse, so there are no import duties or customs surprises, and you are backed by UK-based aftersales support from our team.

Frequently Asked Questions

Which optics fit the American Defense AD-509T Holosun 509T QD Mount Low?
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 the American Defense AD-509T Holosun 509T QD Mount Low give?
This version is low height, which sits the dot low over the rail, below iron-sight height.

Does the American Defense AD-509T Holosun 509T QD Mount Low 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 the American Defense AD-509T Holosun 509T QD Mount Low 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 the American Defense AD-509T Holosun 509T QD Mount Low weigh?
It weighs around 2.3 oz.