The Apex Optic Mount for ACRO/MPS* – Sig P320 Sig-LOC Slide Cut including M17 / M18 Models is a precision-machined adapter that lets you run enclosed emitter optics like the Aimpoint Acro P-1/P-2, Steiner MPS, or Lead & Steel Pandora PB-3 on your P320 Legion or M17/M18 with the factory Sig-LOC (R2) cut. No slide milling, no guesswork—just a direct bolt-on that locks down your optic with zero shift.
| Manufacturer | Apex Tactical Specialties |
|---|---|
| Model | Apex Optic Mount for ACRO/MPS – Sig P320 Sig-LOC Slide Cut |
| Material | 7075-T6 aluminum, hardcoat anodized (per manufacturer specs) |
| Compatibility | Sig Sauer P320 Legion, P320 M17/M18, and all P320 models with factory Sig-LOC (R2) slide cut |
| Finish | Black hardcoat anodized |
| Weight | 0.6 oz (mount only) |
| Condition | New |
Key Features
- Direct Sig-LOC Fitment – Drops into the factory R2 cut on P320 Legions and M17/M18 slides. No filing, no fitting—torque to spec and go.
- Integrated Rear Sight / Gas Shield – The rear sight is built into the mount and sits forward of the optic window, acting as a gas shield. This keeps carbon and debris off your lens longer, meaning less wiping between strings.
- Co-Witness Ready – The integrated sight co-witnesses in the bottom 25% of the optic window, giving you a backup aiming reference without blocking your main sight picture.
- Enclosed Optic Lockup – Uses four screws to clamp the optic body securely, preventing any shift under high-round-count sessions or hard recoil.
- Lightweight and Low Profile – At just 0.6 oz, it adds negligible weight to your slide while keeping the optic deck height as low as possible.
Who It’s For
This mount is for shooters who already run an enclosed emitter optic—Acro, MPS, or Pandora—on a Sig P320 with the factory Sig-LOC cut. If you want a drop-in solution that includes a backup rear sight and a gas shield in one package, this is it. It’s ideal for competition shooters, duty users, and early adopters who want to keep their optic glass clean without adding a separate shield.
Pros & Cons
- Pro: Easy install with no slide modification required.
- Pro: Integrated gas shield reduces lens fouling noticeably.
- Pro: Co-witness rear sight is included—no separate purchase needed.
- Con: Only fits Sig-LOC (R2) cut slides; older P320 models with standard dovetail cuts require a different mounting solution or slide milling.
Comparison
| Feature | Apex Optic Mount | Zev Technologies ACRO Mount for P320 | Agency Arms AOS Plate for P320 |
|---|---|---|---|
| Material | 7075-T6 aluminum | 6061-T6 aluminum | Stainless steel |
| Weight | 0.6 oz | 0.8 oz | 1.2 oz |
| Integrated Rear Sight | Yes | No (separate plate) | No (requires AOS optic system) |
| Gas Shield | Yes (built into sight) | No | No |
| Compatibility | Sig-LOC cut only | Standard dovetail cuts | Proprietary AOS cut |
| Price | $65 | $85 | $110 |
Compared to Zev’s standard ACRO plate, the Apex mount adds a rear sight and gas shield at a lower price point. Agency’s AOS is a full system swap—more expensive and less drop-in. For Sig-LOC slide owners, the Apex mount is the most feature-rich option under $70.
FAQ
Does this mount work with the Sig P320 M18?
Yes. The M18 uses the same Sig-LOC (R2) slide cut as the M17 and Legion models. This mount is a direct fit.
Can I use this mount without the integrated rear sight?
This version includes the integrated rear sight/gas shield. Apex also offers a version without the sight if you prefer a clean top deck, but the sight version gives you backup irons and gas protection in one unit.
Will this mount fit an Aimpoint Acro P-1?
Yes. The mount is compatible with both the Acro P-1 and P-2, as well as the Steiner MPS and Lead & Steel Pandora PB-3.
Do I need to modify my slide to install this?
No. It drops into the factory Sig-LOC cut. Just remove the existing cover plate, install the mount with the included screws, and torque to spec.
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Last updated: April 2026
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