Apex Optic Mount Holoson 509T to SIG P320 with SIG-LOC Optic Cut

Description

Living on the Florida coast means dealing with salt air, humidity, and sand—three things that can ruin an unprotected firearm in a hurry. The Apex Optic Mount for the Holosun 509T to SIG P320 with SIG-LOC Optic Cut is built specifically for that environment. Machined from solid billet steel with a black oxide finish, this mount resists corrosion and holds up to daily carry in coastal conditions.

This mount is designed for the SIG Sauer P320 Legion, P320 M17, M18, and any other P320 model that uses the SIG-LOC optic cut. It securely attaches your Holosun 509T directly to the slide. No adapter plates, no extra wobble—just a direct, solid fit.

One of the most practical features is the integrated rear sight. It sits in front of the optic, acting as a gas shield that keeps carbon and debris off your lens. If you’ve ever cleaned a carry optic after a range session, you know how much this matters. The rear sight is set to co-witness in the bottom 25% of the optic window, so your dot stays visible while the sight remains usable as a backup. A tall front sight is included with the mount—just select the right height option based on your barrel length.

For those who prefer the rear sight behind the optic, there’s a version with a blast deflector block that does the same job without blocking your view through the glass. Either way, your optic stays cleaner longer.

Key specs and fitment details:

• Material: Billet steel, black oxide finish—corrosion-resistant and tough enough for saltwater air and sandy pockets.
• Compatibility: SIG Sauer P320 with SIG-LOC optic cut (Legion, M17, M18, and others). Works with factory Loaded Chamber Indicator on M17/M18 models.
• Optic: Holosun 509T only.
• Hardware: Thread Locking Patch pre-applied to screws. Torque to 20 in-lb. No extra thread locker needed.
• Sight regulation: POA = POI at 10 yards with 115 grain ammunition.
• Co-witness: Integrated rear sight co-witnesses in the bottom 25% of the optic window. Tall front sight included with purchase.
• Gas shield: Integrated into the rear sight base (front-sight version) or a dedicated blast deflector block (rear-sight version). Both keep your objective lens cleaner.

If you don’t need backup iron sights, the same