American Defense AD-509T Mount — Holosun 509T Co-Witness

The AD-509T QD mount is a compact, one-piece mounting solution developed for the Holosun 509T red dot and platforms that require a small, lightweight optic interface. It is precision machined and finished to military-style specifications and features a quick-disconnect system designed to accommodate a range of rail tolerances. The mount delivers co-witness height suitable for AR pistols and other firearms configured to use the Holosun 509T footprint.

Key Specifications

• The mount is a one-piece unit precision machined from 6061 T6 aluminum.
• The exterior is finished in hard coat T3 Mil-Spec anodize for corrosion resistance.
• Designed specifically to fit the Holosun 509T footprint.
• The model designation is AD-509T.
• The product provides a co-witness optic height.
• Color is specified as Black.
• Feature described as Quick Release for rapid attachment/removal.
• Incorporates the Patented QD Auto Lock Lever system to accommodate varied rail tolerances.
• Product Type is listed as Mount.
• Subcategory is Optic Specific Mounts.

Compact and deliberately engineered, the AD-509T mount pairs directly with the Holosun 509T footprint to provide a secure, repeatable optic interface. Its one-piece construction and QD Auto Lock Lever make it a practical choice for users who need a dependable co-witness mounting solution that balances lightweight design with rugged construction.