Apex Optic Mount for ACRO/MPS* – Sig P320 Sig-LOC Slide Cut including M17 / M18 Models

Optic Mount – ACRO / MPS – Sig P320 R2 Slide Cut (M17 / M18 / Legion)

This optic mount adapts the Sig Sauer P320 factory R2 slide cut to accept Aimpoint ACRO P-1/P-2, Steiner MPS, and Lead & Steel Pandora PB-3 footprints. It replaces the factory optic plate, providing a direct, rigid mounting surface with no adapter shims. The version with the integrated rear sight places the notch forward of the optic window, which also functions as a gas shield to reduce debris buildup on the lens. For models without an integrated rear sight, use your existing suppressor-height rear or a dedicated optic-only setup.

Compatibility

• Sig Sauer P320 – all models with factory R2 slide cut (Legion, X-Five, X-Carry, etc.)
• Sig Sauer M17 / M18 – both standard and optics-ready versions
• Factory Loaded Chamber Indicator (LCI) – no modification required
• Optics: Aimpoint ACRO P-1, ACRO P-2, Steiner MPS, Lead & Steel Pandora PB-3

Key Features

• Direct-fit for R2 cut slides – no adapter plates or slide modifications
• Integrated rear sight (select models) – notch forward of optic, co-witnesses at bottom 25% of window
• Gas shield design – integrated rear sight deflects debris away from optic lens
• Tall front sight required for co-witness – two sight height options available based on barrel length
• Sights regulated for POA=POI at 15 yards with 124 gr. NATO ammunition (integrated rear sight models only)
• Compatible with factory LCI – no removal or filing needed

Install Difficulty: 2 / 5

Drop-in fit. Requires removal of factory optic plate (Torx T10 or T15), application of thread locker (not included), and torque wrench set to 15 in-lbs. If installing the integrated rear sight version, verify front sight height per barrel length. No slide milling or fitting required.

FAQ

Will this mount work on a P320 X-Compact with R2 cut?

Yes, provided your slide has the factory R2 cut (three mounting lugs). The X-Compact R2 slides accept this mount without issue. Verify front sight height if using the integrated rear sight version.

Can I use this mount without the integrated rear sight?

Yes. The mount is available in two configurations: with integrated rear sight (co-witness + gas shield) or without (optic-only). Both versions use the same R2 footprint and optic compatibility.

Do I need to remove the factory Loaded Chamber Indicator?

No. This mount is designed to clear the factory LCI on M17/M18 and other R2-cut slides. No modification to the LCI assembly is required.

All mounts ship with necessary hardware. Warranty against manufacturing defects – 1 year from purchase. In-stock orders ship within 1 business day.