{"product_id":"american-defense-ad-509t-lower-1-3-co-witness","title":"American Defense AD-509T Holosun 509T QD Mount Lower 1\/3 Co-Witness – AD-509T-11-STD","description":"\u003cp\u003eThe \u003cb\u003eAmerican Defense AD-509T\u003c\/b\u003e is a quick-detach rifle mount purpose-built for optics using the \u003cb\u003eHolosun 509T footprint\u003c\/b\u003e — this version at \u003cb\u003elower 1\/3 co-witness height\u003c\/b\u003e, raising the dot so iron sights appear in the lower third of the window. ADM's patented \u003cb\u003eAuto Lock QD lever\u003c\/b\u003e attaches and removes the optic fast while holding a secure, repeatable return-to-zero on Picatinny rails.\u003c\/p\u003e\u003cp\u003eMachined from 6061-T6 aluminium with a Type III hardcoat anodised finish. Made in the USA.\u003c\/p\u003e\u003cp\u003e\u003cb\u003eHeight:\u003c\/b\u003e Lower 1\/3 Co-Witness — also available in \u003ca href=\"\/products\/american-defense-ad-509t-holosun-509t-quick-detach-mount\"\u003eLow Mount\u003c\/a\u003e and \u003ca href=\"\/products\/american-defense-ad-509t-absolute-co-witness\"\u003eAbsolute Co-Witness\u003c\/a\u003e.\u003c\/p\u003e\u003cp\u003e\u003cb\u003eHow It Compares\u003c\/b\u003e\u003c\/p\u003e\u003cp\u003eRunning an AEMS optic instead? See the \u003ca href=\"\/products\/american-defense-mfg-holosun-aems-qd-optic-mount\"\u003eAD-AEMS mount\u003c\/a\u003e. Browse all \u003ca href=\"\/collections\/red-dot-sight-mounts\"\u003ered dot mounts\u003c\/a\u003e and \u003ca href=\"\/collections\/enclosed-red-dot-sights\"\u003eenclosed red dots\u003c\/a\u003e; read our \u003ca href=\"\/blogs\/news\/red-dot-co-witness-heights-explained\"\u003eco-witness heights guide\u003c\/a\u003e.\u003c\/p\u003e\u003cp\u003e\u003cb\u003eIdeal For\u003c\/b\u003e\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003eHolosun 509T optics on rifles\/carbines\u003c\/li\u003e\n\u003cli\u003eLower 1\/3 co-witness AR setups\u003c\/li\u003e\n\u003cli\u003eQuick-detach with return-to-zero\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003e\u003cb\u003eKey Features\u003c\/b\u003e\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003ePurpose-built for Holosun 509T footprint\u003c\/li\u003e\n\u003cli\u003eLower 1\/3 co-witness height\u003c\/li\u003e\n\u003cli\u003eADM Auto Lock quick-detach lever; return-to-zero\u003c\/li\u003e\n\u003cli\u003e6061-T6 aluminium, Type III hardcoat; ~2.3 oz; USA-made\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003e\u003cb\u003eTechnical Specifications\u003c\/b\u003e\u003c\/p\u003e\u003ctable\u003e\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cb\u003eFits\u003c\/b\u003e\u003c\/td\u003e\n\u003ctd\u003eHolosun 509T footprint\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cb\u003eMount\u003c\/b\u003e\u003c\/td\u003e\n\u003ctd\u003ePicatinny (Auto Lock QD)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cb\u003eHeight\u003c\/b\u003e\u003c\/td\u003e\n\u003ctd\u003eLower 1\/3 co-witness\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cb\u003eMaterial\u003c\/b\u003e\u003c\/td\u003e\n\u003ctd\u003e6061-T6, Type III hardcoat\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cb\u003eWeight\u003c\/b\u003e\u003c\/td\u003e\n\u003ctd\u003e~2.3 oz\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cb\u003eMPN \/ UPC\u003c\/b\u003e\u003c\/td\u003e\n\u003ctd\u003eAD-509T-11-STD \/ 810008517642\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\u003c\/table\u003e\u003cp\u003e\u003cb\u003eWhat's Included\u003c\/b\u003e\u003c\/p\u003e\u003cul\u003e\u003cli\u003eAmerican Defense AD-509T QD mount (lower 1\/3 co-witness), mounting hardware\u003c\/li\u003e\u003c\/ul\u003e\u003cp\u003e\u003cb\u003eUK Delivery \u0026amp; Support\u003c\/b\u003e\u003c\/p\u003e\u003cp\u003eUK-stocked and dispatched tracked from our UK warehouse — no import duties or customs delays — backed by UK-based support and ADM's lifetime warranty.\u003c\/p\u003e\u003cp\u003e\u003cb\u003eFrequently Asked Questions\u003c\/b\u003e\u003c\/p\u003e\u003cp\u003e\u003cb\u003eWhich optics fit?\u003c\/b\u003e\u003cbr\u003eOptics using the Holosun 509T footprint (e.g. HE509T \/ HS509T).\u003c\/p\u003e\u003cp\u003e\u003cb\u003eWhat does lower 1\/3 co-witness mean?\u003c\/b\u003e\u003cbr\u003eThe optic sits slightly higher than the irons, so they appear in the lower third of the window for a cleaner sight picture.\u003c\/p\u003e\u003cp\u003e\u003cb\u003eDoes it return to zero?\u003c\/b\u003e\u003cbr\u003eYes — the Auto Lock QD lever gives repeatable return-to-zero.\u003c\/p\u003e","brand":"American Defense Mfg.","offers":[{"title":"Default Title","offer_id":58230171959670,"sku":"AD-509T-11-STD","price":189.99,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0337\/3216\/5771\/files\/american-defense-ad-509t-holosun-509t-quick-detach-mount-red-dot-mount-american-defense-mfg-lower-13-co-witness-310806.jpg?v=1772595715","url":"https:\/\/xtremetactical.co.uk\/products\/american-defense-ad-509t-lower-1-3-co-witness","provider":"Xtreme Tactical","version":"1.0","type":"link"}