This optic mount provides a direct, secure interface for closed-emitter optics on Sig Sauer P320 slides cut to the -R2 (Sig-LOC) footprint. It solves the problem of mounting an Aimpoint ACRO or Steiner MPS to P320 Legion, M17, or M18 slides without adapter plates or aftermarket slide milling, while maintaining a functional iron sight solution. The integrated rear sight sits forward of the optic window and doubles as a gas shield, reducing carbon buildup on the lens during suppressed or high-round-count strings.
Compatibility
- Sig Sauer P320 models with factory -R2 (Sig-LOC) slide cut
- Sig Sauer P320 Legion (full-size, X-Five, X-Carry)
- Sig Sauer P320 M17 / M18 (commercial and military variants)
- P320 slides with factory Loaded Chamber Indicator
- Optics: Aimpoint ACRO P-1, ACRO P-2, Steiner MPS, Lead & Steel Pandora PB-3
Key Features
- Direct-fit to -R2 cut slides — no adapter plate required
- Integrated rear sight positioned forward of the optic window
- Rear sight acts as a gas shield to reduce lens fouling
- Co-witness alignment: bottom 25% of optic window with a tall front sight
- Sight regulation: POA = POI at 15 yards with 124-gr NATO ammunition (integrated rear sight version)
- Two front sight height options available — select based on barrel length
- Maintains function of factory Loaded Chamber Indicator
- Ships with mounting screws; no additional adapter hardware required
Install Difficulty: 2 / 5
Requires a #6 Torx driver (T6 or T7 depending on screw spec), a small flathead screwdriver for the extractor plunger if swapping sights, and a non-marring punch for front sight installation. Do not exceed 12 in-lbs on optic mount screws. Front sight swap is recommended but not mandatory if your existing front sight is tall enough for the co-witness plane.
FAQ
Will this mount fit a standard P320 slide without the -R2 cut?
No. This mount is designed exclusively for slides with the factory -R2 (Sig-LOC) footprint. Standard P320 slides with the earlier Romeo1/Delta Point Pro pattern require a different adapter.
Do I need to remove the rear sight to install this mount?
Yes. The integrated rear sight replaces the factory dovetail rear sight entirely. You will need to drift out the OEM rear sight before mounting the optic plate. The front sight may need to be swapped to a taller option depending on barrel length and your chosen kit.
Which front sight height do I need?
Two height options are available based on barrel length. Select the shorter front sight for 4.7″ barrels (Legion X-Five, M17) and the taller front sight for 3.9″ barrels (M18, X-Carry). Both provide a bottom-25% co-witness with the integrated rear sight.
All orders ship within one business day. This mount carries a limited lifetime warranty against manufacturing defects. Return requests accepted within 30 days of delivery if unused and in original packaging.
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