Apex Optic Mount for Holosun 509T to Sig P320 RX PRO Cut

Description

For Sig Sauer P320 owners with an RX Pro cut slide, the Apex Optic Mount provides a dedicated solution for mounting the Holosun 509T red dot. Priced at $65, this mount is machined from a single billet of steel and finished with a black oxide coating for corrosion resistance and a low-glare appearance. The steel construction offers a stable platform for the optic, reducing the chance of shifting under recoil compared to some polymer or aluminum alternatives.

This mount is designed specifically for the P320 RX Pro slide cut, which means it fits the factory footprint without the need for additional adapter plates or modification. It also works with M17, M18, and Legion slide variants that share the same cut. For California-compliant P320 owners, the mount is compatible with slides that retain the factory Loaded Chamber Indicator (LCI), so you won’t lose that visual or tactile confirmation of a round in the chamber.

Key Benefits for Your Setup

• Steel Construction: Billet steel provides a rigid base for the Holosun 509T, helping maintain zero through repeated use. The black oxide finish resists wear and matches the look of factory Sig parts.
• Direct Fit for RX Pro Slides: No adapter plates or shims required. The mount bolts directly to the slide’s existing holes, keeping the optic low and reducing the overall height of the sight system.
• LCI Compatible: Works with slides that have the factory Loaded Chamber Indicator, so you maintain that important safety feature without interference from the optic mount.
• Holosun 509T Specific: Engineered to securely hold the 509T’s unique footprint. The mount uses the optic’s side clamping system for a positive lock-up that resists movement from slide cycling.
• Cost-Effective Upgrade: At $65, this mount offers a purpose-built solution without the premium of multi-optic plates that may not fit as precisely.

Specifications & Fitment

• Compatible with Sig Sauer P320 slides featuring the RX Pro cut (including factory-cut slides from Sig).
• Also fits M17, M18, and Legion slide models with the RX Pro cut.
• Designed exclusively for the Holosun 509T optic (not compatible with other Holosun models like the 507C or 508T).
• Includes necessary mounting screws for the optic to the mount (verify your slide’s screw size if replacing an existing plate).
• Overall height addition: approximately 0.150 inches above the slide deck (var