Upgraded Sig Sauer P320-M18 w/ Wilson Combat Grip – 9mm
Adopted by the United States Military as the official sidearm of the Marine Corps (and the compact variant of the Army’s M17), the Sig Sauer P320-M18 delivers uncompromising reliability, military-grade durability, and unparalleled modularity. Built around Sig’s innovative serialized Fire Control Unit (FCU), the M18 is a striker-fired powerhouse equipped with an optic-ready slide.
This specific M18 takes that battle-proven foundation and elevates it with premium tactical upgrades. It has been fitted with a highly desirable Wilson Combat grip module, drastically improving ergonomics and traction, alongside a Wilson Combat extended slide release for faster, more positive reloads under pressure. The addition of a factory Sig Sauer flat-faced trigger provides a cleaner, 90-degree break over the standard curved trigger. Complete with three factory magazines and all its original parts, this is a phenomenal, turn-key package for duty use, home defense, or high-performance range days.
Product Specifications
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Manufacturer: Sig Sauer (Newington, New Hampshire)
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Model: P320-M18 (Upgraded)
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Caliber: 9x19mm Parabellum (9mm Luger)
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Action: Striker-Fired (Serialized Fire Control Unit)
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Capacity: 21 Rounds / 17 Rounds
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Barrel Length: 3.9 inches (Carbon steel)
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Trigger Upgrade: Factory Sig Sauer Flat-Faced Trigger (provides increased leverage and a crisp, clean 90-degree break).
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Grip Module: Upgraded Wilson Combat P320 Carry Grip Module (features enhanced starburst stippling, an undercut trigger guard, and a revised grip angle).
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Controls Upgrade: Wilson Combat Extended Slide Release.
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Sights: SIGLITE front night sight and a removable night sight rear plate (fully optic-ready for the DeltaPoint Pro / ROMEO1PRO footprint).
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Finish: Coyote Tan PVD coated stainless steel slide.
Condition Report
This upgraded M18 is a previously owned but extremely well-cared-for pistol. It shows minimal signs of standard handling and remains mechanically flawless, with the upgrades seamlessly integrated.
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Finish: Retains approximately 95%+ of its original Coyote Tan PVD slide finish. There is faint, typical operational wear on the barrel hood from the slide cycling, but no deep scratches, rust, or heavy holster wear.
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Bore: Excellent. The bore is bright and highly reflective with strong, sharp rifling.
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Frame: The upgraded Wilson Combat polymer grip module is in perfect condition with zero structural modifications. The original Sig Sauer factory grip module is also included and remains in excellent shape.
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Mechanics: The striker-fired action is incredibly smooth. The Sig flat trigger provides a distinctly superior, crisp break compared to the standard military trigger. The Wilson Combat extended slide release functions perfectly, and the ambidextrous manual safety engages with a positive, tactile click.
Included Accessories
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Magazines: Includes three (3) factory Sig Sauer steel magazines—two (2) 21-round extended magazines and one (1) 17-round flush-fit magazine.
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Original Parts: Comes complete with the original factory Sig Sauer black grip module, allowing you to swap back to the military configuration in seconds.
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Original Packaging: Ships in the original Sig Sauer factory hard plastic case.
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Paperwork/Tools: Includes the original owner’s manual and factory materials.
























