First Look: Apex Optic Mount Holoson 509T for the SIG P320

Includes a raised front and rear iron sight for a lower 25-percent co-witness.

posted on May 10, 2024
Apex Optic Mount Holoson 509T For The SIG P320

Apex Tactical, known for its high-end, aftermarket accessories designed for a large number of makes and models of popular handguns, has now launched a new optics plate for the SIG Sauer P320 series using the SIG LOC slide cut that accommodates the popular Holosun 509T enclosed emitter reflex sight. This new optics mounting plate from Apex Tactical (part 112-013-C) is specifically designed to mate with SIG Sauer P320 slides that use the SIG LOC optics cut. This cut can be found on models such as the SIG Sauer P320 Legion and the military style M17 and M18 among other models. 

Unlike most optics-mounting plates, this new unit from Apex Tactical has back-up rear sights built into the front portion of the plate itself. Not only does having the extra structure there help cradle the red-dot sight in place, but the material also helps catch some of the carbon and other fouling from shooting that would otherwise end up soiling an optics objective lens. As far as sights are concerned, the built-in rear sight is designed to co-witness with the bottom 25 percent of the available viewing area of the Holosun 509T red-dot sight. Finally, the built-in rear sight in front on the plate removes the need for the user to source and install an aftermarket, taller rear sight that would be mounted behind the optic. Although a taller than normal front sight blade will also be necessary, Apex Tactical includes one with this new optics mounting plate. In fact, customers are able to choose from two different sight and plate packages depending on the front-sight height they require for their specific SIG Sauer P320 variant. For those who are interested in mounting the Holosun 509T without a built in sight, Apex Tactical also offers a standard optics plate. To learn more about these optics mounting plates, please visit


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