SIG SAUER FIRE CONTROL UNITS (FCUs) are the serialized core of SIG’s modular handgun systems, allowing shooters to build, configure, and customize compatible P320 and P365 platforms around a factory SIG Sauer chassis.

Unlike traditional handguns where the frame itself is the serialized firearm component, SIG’s modular FCU design allows the user to swap grip modules, slides, barrels, optics, magazines, and accessories while retaining the same serialized fire control unit.

This flexibility has made the FCU platform one of the most innovative handgun systems available, supporting everything from deep-concealment carry builds to competition and duty-oriented configurations.

Available Configurations Include:

• P365 FCUs: Modular foundations for micro-compact and carry-focused builds
• P320 FCUs: Full-size, compact, and competition-oriented modular systems
• Custom Works FCUs: Premium factory configurations with upgraded triggers and finishes

Why the SIG FCU System Matters:
The FCU allows the shooter to configure the handgun around the mission instead of being locked into a single frame size or setup. This modularity supports easier customization, simplified upgrades, and long-term adaptability within the SIG Sauer ecosystem.

Important Note:
Fire Control Units are serialized firearm components and must ship to a Federal Firearms License holder for transfer.

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